New perspectives on norms and complexity

Norm complexity has only recently emerged as a prominent issue in International Relations (IR) norms research. While early norms scholars understood norms as embedded in larger normative structures (Finnemore and Sikkink Reference Finnemore and Sikkink1998: 897; Florini Reference Florini1996: 476), their research remained ‘atomistic’ in practice (Pratt Reference Pratt2020: 64). Focussing on trajectories of individual norms, scholars discussed ‘fit’ or ‘match’ with pre-existing norms as one among several factors facilitating norm adoption and diffusion (Checkel Reference Checkel1999: 86; Florini Reference Florini1996: 376–77). Successive scholarship problematized the ‘norm life cycle’ model and highlighted norms’ contestedness and malleability (Deitelhoff and Zimmermann Reference Deitelhoff and Zimmermann2019; Hurd Reference Hurd2007; Iommi Reference Iommi2020; Krook and True Reference Krook and True2012; Sandholtz Reference Sandholtz2008; Wiener Reference Wiener2018). Yet, it still focused on individual norms, addressing fit and conflicts with other norms as conditions influencing their contestation or erosion (Deitelhoff and Zimmermann Reference Deitelhoff and Zimmermann2019: 13; Sandholtz Reference Sandholtz2008: 101, 109; Wiener and Puetter Reference Wiener and Puetter2009: 14).

In contrast, many recent contributions put relations and interactions between global norms as well as norms’ internal complexity at the centre of analysis (Berger Reference Berger2023; Bloomfield Reference Bloomfield, Hehir and Murray2017; Buitelaar and Hirschmann Reference Buitelaar and Hirschmann2021; Donovan Reference Donovan2018; Fehl Reference Fehl2019, Reference Fehl2023; Fehl and Rosert Reference Fehl and Rosert2020; Gallagher et al Reference Gallagher, Lawrinson and Hunt2022; Gholiagha Reference Gholiagha2023; Gholiagha, Holzscheiter, and Liese Reference Gholiagha, Holzscheiter and Liese2020; Jay and Killingsworth Reference Jay and Killingsworth2024; Jurkovich Reference Jurkovich2020; Kreuder-Sonnen Reference Kreuder-Sonnen2019; Lantis and Wunderlich Reference Lantis and Wunderlich2018, Reference Lantis and Wunderlich2022; Lesch Reference Lesch2021; Moore Reference Moore2025; Orchard Reference Orchard, Hunt and Orchard2020; Paddon Rhoads and Welsh Reference Paddon Rhoads and Welsh2019; Peltner Reference Peltner2017; Pratt Reference Pratt2020; Rosert Reference Rosert2019a, Reference Rosert2024; Saltnes Reference Saltnes2017; Staunton and Ralph Reference Staunton and Ralph2020; Winston Reference Winston2018, Reference Winston2023; Wisken and Kreuder-Sonnen Reference Wisken, Kreuder-Sonnen, Seline, Nikolaos and Rozemarijn2020).

Like IR norms research in general (Orchard and Wiener Reference Orchard, Wiener, Orchard and Wiener2024), this strand of inquiry is marked by a theoretical and analytical diversity that makes it difficult to see shared research interests and the potential of different studies to provide complementary insights into similar political dynamics.

Theoretically, the mainstream definition of norms as ‘standard[s] of appropriate behaviour for actors with a given identity’ (Finnemore and Sikkink Reference Finnemore and Sikkink1998: 891) and the life cycle model are prominent points of reference (Fehl Reference Fehl2023: 754; Rosert Reference Rosert2024: 26; Winston Reference Winston2018: 639, 645; Wright Reference Wright2023: 26), but so is a critical constructivist understanding of norms as inherently contested ‘structures of meaning-in-use’ (Wiener Reference Wiener2018: 54; cited in Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020: 297; Lantis and Wunderlich Reference Lantis and Wunderlich2018: 571; Winston Reference Winston2018: 645). Some analysts combine a constructivist understanding of norms as intersubjective with a rationalist notion of strategic action (Kreuder-Sonnen Reference Kreuder-Sonnen2019; Wisken and Kreuder-Sonnen Reference Wisken, Kreuder-Sonnen, Seline, Nikolaos and Rozemarijn2020). Yet others draw on pragmatist theory to highlight arrangements of ‘orders of worth’ inherent to norms (Lesch Reference Lesch2021) or to replace the study of ‘norms’ with studying ‘normative configurations’ (Pratt Reference Pratt2020). Analytically, some studies ‘zoom in’ to unpack norms’ internal complexity (Bloomfield Reference Bloomfield, Hehir and Murray2017; Donovan Reference Donovan2018; Jurkovich Reference Jurkovich2020; Lesch Reference Lesch2021; Pratt Reference Pratt2020; Winston Reference Winston2018) whereas others ‘zoom out’ to investigate norms’ relations with other norms and their embeddedness in larger structures (Buitelaar and Hirschmann Reference Buitelaar and Hirschmann2021; Fehl Reference Fehl2023; Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020; Lantis and Wunderlich Reference Lantis and Wunderlich2018; Saltnes Reference Saltnes2017).

Yet, despite their diversity, all analyses share core assumptions and interests and can hence be read as contributing to a joint but pluralist research agenda. All subscribe to a constructivist understanding of norms as intersubjective structures conveying meaning and moral guidance. All emphasize that norms are subject to interpretation and contestation. Finally, all share an interest in relations between multiple elements of normative structure and their political effects.

Emphasizing shared assumptions and interests does not imply that diversity should be ignored. Rather, I aim to invite conversations across theoretical divides within IR constructivism (McCourt Reference McCourt2016) and to foreground connections between different phenomena, such as internal and external complexity, collisions and clusters. To do so, I spell out a thus far implicit research agenda, showing how existing work contributes different insights to a shared programme, but also what blind spots have yet to be tackled.

In structuring this agenda, I use the more established research agenda on regime complexity as a point of reference. Norm complexity research is connected to long-standing work on regime complexity in global politics,Footnote ³ but cannot be subsumed under it. In delineating the two agendas, I highlight both the novel contributions of norm complexity research and how both lines of inquiry complement one another.

While regime complexity and norm complexity research are both interested in relations between different elements of larger structures in global governance, they differ in their primary object of analytical interest. Regime complexity scholarship is concerned with relations between centres of authority: Why do different inter- and transnational institutions raise ‘rival authority claims’ (Alter and Raustiala Reference Alter and Raustiala2018: 332) over an issue-area? When do they accept hierarchical relations marked by ‘deference’ (T. Pratt Reference Pratt2018)? How do rival or hierarchical authority relations shape political outcomes? In contrast, norm complexity research analyses relations between internationally shared ideas and practices at the level of meaning: Do values and practices contained in different norms align or contradict one another? How are they argumentatively linked? And what are the political consequences of (re)connecting them in certain ways? In short, regime complexity research focuses on complex authority structures while norm complexity research investigates complex normative structures.

Regime complexity and norm complexity can be empirically connected. Overlapping authority claims by different institutions can give rise to collisions between normative ideas associated with these institutions and can be leveraged by supporters and opponents of these ideas. This dynamic has been explored by the collaborative ‘interface conflicts’ project (Faude and Fuss Reference Faude and Fuss2020; Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020; Kreuder-Sonnen and Zürn Reference Kreuder-Sonnen and Zürn2020; Krisch, Corradini and Reimers Reference Krisch, Corradini and Reimers2020; Mallavarapu Reference Mallavarapu2020).

Yet, regime complexity is not always at play when different normative ideas and practices become related in politically powerful ways. For instance, norms scholars highlight normative trade-offs made within a single centre of authority on issues such as conditioning development aid (Saltnes Reference Saltnes2017), dealing with International Criminal Court (ICC) arrest warrants (Jay and Killingsworth Reference Jay and Killingsworth2024) or balancing peacekeeping with human rights obligations (Buitelaar and Hirschmann Reference Buitelaar and Hirschmann2021).Footnote ⁴ They also study positive linkages between norms, for instance between protection and prosecution norms (Fehl Reference Fehl2019, Reference Fehl2023), ‘norm clusters’ relating multiple behaviours to a shared value (Winston Reference Winston2018), as well as complex structures within individual norms (e.g. Donovan Reference Donovan2018; Lesch Reference Lesch2021; Pratt Reference Pratt2020).

To summarize, the study of norm complexity broadens the analytical scope beyond institutional configurations addressed by regime complexity theory, but also deepens the latter by making visible complex meaning structures that shape or are shaped by regime complexity. In addition, norm complexity research foregrounds modes and logics of agency that regime complexity researchers have only begun to address. Most work on regime complexity analyses actors’ engagement with complex global governance structures from a rationalist perspective and with a focus on behavioural agency and institutional strategies such as forum-shopping (Busch Reference Busch2007), regime-shifting (Helfer Reference Helfer2009), or the brokering of inter-organizational conflicts (Hofmann Reference Hofmann2019). However, this still predominant focus on rational institutional agency has been opened by regime complexity scholars who emphasize intersubjective perceptions of institutional overlaps (Kreuder-Sonnen and Zürn Reference Kreuder-Sonnen and Zürn2020; Orsini et al Reference Orsini, Morin and Young2013), the justificatory practices used by international organizations to manage overlaps (Faude and Groβe-Kreul Reference Faude and Groβe-Kreul2020) or the discursive construction of issue-linkages in a regime complex (Muzaka Reference Muzaka2011). Norm complexity research can advance this line of theorizing, while also demonstrating that linking different normative ideas and practices can unfold powerful effects beyond situations of formal institutional overlap.

A pluralist agenda

I have argued above that research on norm complexity in international politics adds both to research on individual norms and to research on international regime complexity. Using the latter as a point of reference, I structure the norm complexity research agenda around three tasks that both mirror and add to studies of regime complexity. Given the pluralism of the field, I assume that each task can be approached from different constructivist perspectives on norms and normativity.Footnote ⁵

The first task consists of mapping norm complexity. Just like studies of regime complexity describe and catalogue complex authority structures, recent analyses of norm complexity are taking stock of meaning structures comprising multiple normative elements in a given field of study. Some scholars emphasize issue-specific ‘constellation[s] of normative bases’ (Pratt Reference Pratt2019: 783), whereas others identify more general types of complex structures, including clusters and bundles (Winston Reference Winston2018; Lantis and Wunderlich Reference Lantis and Wunderlich2018), hierarchies (Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020: 308; Harman Reference Harman2017), conflicts and collisions (Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020; Saltnes Reference Saltnes2017) and hybrids (Fehl Reference Fehl2019; Lesch Reference Lesch2021). In addressing the first task, norm complexity research goes beyond analysing formal treaties and organizations to include informal norms such as peacekeeping principles (Buitelaar and Hirschmann Reference Buitelaar and Hirschmann2021) or development norms emphasized in European Union (EU) policy documents (Saltnes Reference Saltnes2017). Given their assumptions about norms’ contested nature, scholars of norm complexity also highlight the intersubjectivity and dynamism of complex normative structures (Fehl Reference Fehl2019; Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020; Winston Reference Winston2023). Rendering such informal and dynamic structures visible is methodologically demanding, since researchers must analyse a wide set of sources at repeated points in time. Mapping norm complexity requires field-specific qualitative assessments, as noted by Fuß et al (Reference Fuß, Kreuder-Sonnen, Saravia and Zürn2021: 11–12) and Gholiagha (Reference Gholiagha2023: 152) with regard to interface conflicts and norm collisions. As part of a cumulative research agenda on norm complexity, scholars should therefore continue to connect field-specific mapping studies – including but not limited to norm conflicts – to enable comparisons of policy areas and regions in terms of their normative integration or fragmentation.

Such comparative work is indispensable as a basis for addressing the second task: understanding causes and consequences of norm complexity. Here, too, norms research echoes research into the causes and consequences of regime complexity while modifying and expanding it to analyse connections between normative ideas and practices. Given the constructivist nature of the research programme, investigations of such causes and effects do not generally take the form of testing law-like generalizations. Instead, researchers search for ‘enabling’ causes and effects of complex configurations and norm relations in specific fields (e.g. Fehl Reference Fehl2023; Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020). They are also specifically interested in how complexity both shapes and is shaped by norm dynamics (Winston Reference Winston2023: 3). For instance, Lantis and Wunderlich (Reference Lantis and Wunderlich2018) attribute the resiliency of the nuclear disarmament norm to its embeddedness in a larger nuclear norms cluster; Elvira Rosert (Reference Rosert2024: 12) relates declining attention to the protection of combatants in the law of armed conflict to the ‘permissive effect’ of the newer ‘protection of civilians’ norm.

The third task is where I see most potential for advancing the norm complexity research agenda. It moves the focus from structures and ‘system effects’ (Winston Reference Winston2023: 2) to studying agency in complex normative environments. Regime complexity research has long explored how global actors both create and respond to complex institutional structures, focusing on rational institutional agency through strategies like forum-shopping. For scholars of norm complexity, the analogous task is to understand how political agency on global issues is constrained, enabled and shaped by complex normative structures and how, conversely, these complex structures are created and changed through political agency – in contexts marked by regime complexity (similarly Gholiagha Reference Gholiagha2023) but also beyond them.

Most existing studies focus on the first part of the task: investigating the impact of complexity on agency. Some conceive relations and interactions between norms as constraining agency: the permissive effect of a norm impedes norm entrepreneurship on another norm (Rosert Reference Rosert2024: 12); a norm’s embeddedness in a cluster limits actors’ ability to contest it (Lantis and Wunderlich Reference Lantis and Wunderlich2018). Other contributions investigate actors’ responses to and uses of complexity: their prioritisation (Jay and Killingsworth Reference Jay and Killingsworth2024; Saltnes Reference Saltnes2017) or reconciliation (Buitelaar and Hirschmann Reference Buitelaar and Hirschmann2021; Krisch et al Reference Krisch, Corradini and Reimers2020: 351) of conflicting norms, their transformation of institutional overlaps into interface conflicts (Faude and Fuss Reference Faude and Fuss2020; Kreuder-Sonnen and Zürn Reference Kreuder-Sonnen and Zürn2020), their activation of dormant norm collisions (Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020) and their strategic use of norm collisions through rhetorical action (Wisken and Kreuder-Sonnen Reference Wisken, Kreuder-Sonnen, Seline, Nikolaos and Rozemarijn2020).

In comparison, scholars have given less systematic attention to how political actors create norm complexity. Most prominently, studies of norm entrepreneurship highlight actors’ construction of linkages between new and pre-existing norms through framing and ‘grafting’ (e.g. Carpenter Reference Carpenter2005; Finnemore and Sikkink Reference Finnemore and Sikkink1998: 98; Price Reference Price1998; Rosert Reference Rosert2019b). Yet, there is no reason to assume that creative agency is limited to norm-promoting actors, to the stage of norm emergence or to positive linkages between norms. In ubiquitous situations, actors argue and struggle over relations between established norms: Do human rights norms support or conflict with rules for containing global pandemics? Do norms on promoting nuclear energy help or hinder the fight against climate change? Crucially, different interpretations of a norm relationship can coexist, suggesting that actors can (re)make complex normative structures. They cannot only activate existing conflicts and collisions (Gholiagha Reference Gholiagha2023; Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020), but also transform collisions into positive associations – and vice versa. Such a creative capacity to re-arrange elements of normative structure is emphasized by some recent contributions with a focus on norms’ internal configurations (Lesch Reference Lesch2021; Pratt Reference Pratt2020; Schmidt and Williams Reference Schmidt and Williams2023), but these analyses have remained unconnected to discussions of clusters, collisions and other inter-norm relations.

The third central task within the larger norm complexity agenda – understanding agency – thus holds strong potential for further theory-building and dialogue across theoretical perspectives. To contribute to both, the following section zooms in on analysing how actors navigate complex normative settings. I propose a concept of navigation that connects internal and external norm complexity, and then show how this concept can be integrated into different constructivist approaches to norms. Specifically, I draw on analyses of strategic norm use, on critical approaches to norm contestation, and on pragmatist analyses of norm-based justification practices to develop three analytical lenses that highlight different drivers and implications of actors’ navigation work. I use examples from the nuclear-climate nexus to demonstrate the plausibility of my theoretical claim: that actors not only respond to but continuously (re)create connections between elements of complex normative structures. I show that the three proposed perspectives capture different aspects of this creative navigation work. Thus, I illustrate – with a focus on one of the three research tasks within the larger norm complexity agenda – the value-added of a pluralist engagement with norm complexity.

The climate-nuclear nexus: Navigating a complex normative triangle

In developing my argument, I draw on examples from a triangle of international policy issues which are regulated by international norms and have come to be linked in multiple, often contradictory ways: climate change, nuclear energy and the proliferation of nuclear weapons. In this complex triangle, formal and informal norms are anchored in international treaties such as the Paris Agreement or the Nuclear Non-Proliferation Treaty (NPT), in mandates and regulatory outputs of international organizations such as the International Atomic Energy Agency (IAEA) or the EU, but also in shared informal understandings and narratives (Dubash Reference Dubash2011).

Each of the three issue-areas is itself marked by normative complexity, as has been demonstrated by previous studies mapping normative structures in the respective fields: climate change and nuclear non-proliferation have been analysed as norm clusters or bundles (Höhne, Kahmann and Lohaus Reference Höhne, Kahmann and Lohaus2023; Lantis and Wunderlich Reference Lantis and Wunderlich2018); nuclear energy is subject to various norms from nuclear safety to radioactive waste management (Caballero-Anthony and Trajano Reference Caballero-Anthony, Trajano, Van Ness and Gurtov2017) and forms part of a looser set of energy governance norms (Dubash and Florini Reference Dubash and Florini2011; Escribano Reference Escribano2015). In addition, norms governing the three issues are connected to one another, yet only partly in fixed and formal ways. While non-proliferation and the right to peaceful use of nuclear energy are formally linked in the NPT’s article IV, other associations between normative ideas and practices in the triangle are established and challenged in ongoing communicative exchanges between international organizations, governments and non-governmental organizations (NGOs) – as part of the creative work of navigating norm complexity.Footnote ⁶ To understand how norms on climate change, nuclear non-proliferation and nuclear energy influence one another, it is therefore necessary to bring this creative political agency into sharper focus.

Conceptualizing navigation

The concept of navigation I propose is grounded in an understanding of norms as internally complex. I build here on previous work highlighting different constitutive elements that individual norms are composed of (Jurkovich Reference Jurkovich2020; Lesch Reference Lesch2021; Pratt Reference Pratt2020; Winston Reference Winston2018). For the purpose of my argument, I distinguish two norm components in particular: general values and specific practices evaluated through the former.Footnote ⁷

Building on this assumption, I argue that internal and external norm complexity are systematically related: A connection between distinct norms is formed when these norms are perceived as having some of their constitutive elements in common. Importantly, the practices and guiding values contained in different norms can be related to one another in varying ways. A norm collision is formed when a practice is connected positively to one guiding value but negatively to another one (similarly, Fehl Reference Fehl2023: 755; Gholiagha Reference Gholiagha2023: 151; Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020: 292). For instance, the practice of nuclear energy production has been linked positively to energy security but negatively to environmental justice (Rehner and McCauley Reference Rehner and McCauley2016), resulting in a perceived clash of norms.

However, collisions are only one manifestation of norm complexity. A practice can be linked positively to different values, creating a perception that different norms converge synergistically on an identical course of action. For instance, objections to nuclear energy production are linked to both environmental justice (Kyne and Bolin Reference Kyne and Bolin2016) and the non-proliferation of nuclear weapons (Bunn Reference Bunn2019). A third option is that different practices are seen as reflecting a shared guiding value, creating a norm cluster (Winston Reference Winston2018). In global climate governance, for example, both differentiated emission reduction targets and financial and technology transfer to the Global South have been tied to the ‘common but differentiated responsibilities’ principle (Barral Reference Barral, Hansen-Magnusson and Vetterlein2017).

In what sense do actors ‘navigate’ such complex configurations? I borrow this metaphor from Schmidt and Williams to capture the idea that ‘agents creatively navigate within structures of constraints and possibilities while creating and altering them in the process’ (Schmidt and Williams Reference Schmidt and Williams2023: 9; see also Kreuder-Sonnen, Schmotz and Zürn Reference Kreuder-Sonnen, Schmotz and Zürn2025: 2). Navigation goes beyond the idea that actors increase complexity by adding new norms to a policy field (as in Winston Reference Winston2018) or by linking norms in formal negotiations (as in Lantis and Wunderlich Reference Lantis and Wunderlich2018). Rather, actors establish, reaffirm and contest associations between norms by constructing (and deconstructing) positive or negative connections between their constitutive elements. This construction work involves normative and causal claims. For instance, the argument that both environmental justice and non-proliferation norms mandate the phase-out of nuclear energy rests on a normative claim (‘nuclear energy policy should be guided by environmental justice’) and on a causal claim (‘civilian nuclear programmes increase the risk of nuclear weapons proliferation’).

The creativity of such navigation work implies that, like the meaning of an individual norm, its position in a complex web of norms cannot be treated as stable structural condition (Krisch et al Reference Krisch, Corradini and Reimers2020: 344). While actors often encounter historically pre-configured sets of norms, their options are not limited to working with these existing configurations, for instance by activating a ‘dormant’ collision (Gholiagha et al Reference Gholiagha, Holzscheiter and Liese2020) or by resolving a norm conflict (e.g. Buitelaar and Hirschmann Reference Buitelaar and Hirschmann2021). Rather, as I demonstrate through my analysis of the climate-nuclear nexus, actors can construct competing versions of a connection between norms, including by transforming positive into negative linkages (and vice versa).

To summarize, the proposed concept of navigation emphasizes actors’ creative capacity to establish and contest relations between norms by (re)connecting the practices and values that form their constitutive elements. This concept is theoretically agnostic in the sense that it is not wedded to either of the different constructivist approaches to norms and normativity that form part of the pluralist field. Yet, it can be integrated into these different approaches, yielding different perspectives on the drivers and implications of actors’ navigation of norm complexity.

In the following, I elaborate three perspectives that focus, respectively, on interests, culture and justification practices to address a set of shared questions about agency in complex normative settings: What drives actors to engage creatively with norm complexity? How does this agency shape the meaning and strength of norms? And how does it reflect and impact power relations and social hierarchies among actors?Footnote ⁸

Perspective I: Navigation as strategic linkage

One set of answers to these questions can be based on an approach to norms that combines constructivist and rationalist assumptions. From this first perspective, political actors link norms strategically to suit their interests, allowing them to weaken or strengthen norms and to gain symbolic power over others.

The argument builds on different strands of IR norms research. Studies of norm emergence highlight the construction of positive linkages between norms as a strategy of norm entrepreneurship. In promoting new international norms, actors ‘graft’ emerging norms onto existing ones, for instance a proposed ban on anti-personnel landmines onto existing norms stigmatizing weapons of mass destruction (Price Reference Price1998: 627–31). In my conceptualization of navigation, this rhetorical ‘manipulation’ (Price Reference Price1998: 628) involves connecting a new practice (e.g. a proposed mine ban) to pre-existing ones (e.g. non-use of weapons of mass destruction) by linking both to a shared guiding value (e.g. discrimination between combatants and civilians).

Strategic norm linkage past the stage of emergence, by actors other than norm entrepreneurs and productive of other norm relations has received less systematic attention. Most notably, recent work on norm collisions shows that state and non-state actors can strategically create norm collisions by invoking different existing norms as being relevant to an issue (Kreuder-Sonnen et al Reference Kreuder-Sonnen, Schmotz and Zürn2025: 3; Wisken and Kreuder-Sonnen Reference Wisken, Kreuder-Sonnen, Seline, Nikolaos and Rozemarijn2020: 133). As argued above, this strategy also involves the construction of – different kinds of – connections between the constitutive elements of different norms.

Arguments about grafting and collisions have remained largely unconnected, but can be combined into a more general argument about strategic norm linkage that highlights actors’ creativity in navigating norm complexity. According to this argument, political actors strategically (re)construct links between norm elements that favour their interests. Consequently, it is not just individual norms which can be subject to strategic manipulation (Bower Reference Bower2015; Hurd Reference Hurd2005, Reference Hurd2007; Sandholtz Reference Sandholtz2008), but also norms’ positions vis-à-vis other norms: by discursively (re)connecting norm elements, a collision may be transformed into a synergistic relationship, or a norm may be attached to or detached from existing norm clusters in support of actors’ political interests.

From a strategic linkage perspective, the material or immaterial interests that drive political actors to such creative engagement with norm complexity can entail establishing and protecting, but also evading or diluting norms. By discursively constructing a norm conflict, actors can justify non-compliance with one norm with the claim that this course of action is required by another norm (Kreuder-Sonnen et al Reference Kreuder-Sonnen, Schmotz and Zürn2025: 3). This strategy makes non-compliance less costly and can be used in specific situations or as a general tactic of ‘norm spoiling’ (Sanders Reference Sanders2018: 273). Alternatively, a norm may be evaded by integrating it into a larger norm cluster, a strategy which gives actors greater freedom to choose from different policy options within the cluster (Fehl Reference Fehl2023: 759).

Just like the manipulation of individual norms, the manipulation of norm relations constitutes a source of symbolic power. Norms circumscribe legitimate actions, and legitimacy is a power resource that actors struggle over when arguing over the meaning of norms (Hurd Reference Hurd2005: 498–503). Depending on its aims, successful strategic linkage can therefore increase or decrease the constraining power of one or both norms being linked, and give actors using linkage (symbolic) power over those manipulated. While norm linkage can pursue similar strategic purposes as institutional strategies analysed by regime complexity scholars, it relies on discourses and practices that are more accessible to a wider set of actors: Small states or non-state actors may find it difficult to engage in successful forum-shopping or rival regime creation (Drezner Reference Drezner2009), but may successfully use strategic norm linkage.

The theory of strategic norm linkage can shed light on international discursive struggles over nuclear energy. The perspective captures efforts by different political actors – the IAEA, the European Commission, EU member state governments and NGOs – to strategically construct different types of connections between norm elements in the climate-nuclear energy-nuclear weapons triangle. It highlights how these navigation strategies produce different versions of the same norm relationships and make different strategic uses of similar linkage arguments.

The worldwide promotion of the peaceful use of nuclear energy was established as an international norm in Article IV of the 1968 NPT and in the IAEA’s statute. The NPT’s Article IV affirms states’ ‘inalienable right’ to the peaceful use of nuclear energy and obliges them to ‘co-operate in contributing (…) to the further development of the applications of nuclear energy for peaceful purposes, (…) with due consideration for the needs of the developing areas of the world’. In the IAEA statute, the promotion of nuclear energy as a core mission of the agency is attached to the values of ‘peace, health and prosperity throughout the world’ (Art. II).

The IAEA, as a ‘norm guardian’ (Efrat and Richemond-Barak Reference Efrat and Richemond-Barak2023: 11) of the civilian use norm, has sought to protect and strengthen the latter through a strategy of norm linkage. Since 2000, the agency has been publishing regular reports on ‘Climate Change and Nuclear Power’, which have been prominently presented at international climate change meetings, and which frame the promotion of nuclear energy as a key strategy of mitigating greenhouse gas emissions. The 2024 edition, for instance, argues that ‘mobilizing financing for investment in nuclear energy will play a critical role in supporting ambitious climate change mitigation and adaptation and in delivering reliable, affordable, clean and modern energy to underpin economic and social development and energy security’ (IAEA 2024: 4). With such statements, the IAEA connects its practice of promoting nuclear energy to additional values beyond those stated in its statute – and thereby to different international norms. This rhetorical strategy serves to strengthen the agency’s mission and institutional purpose.

However, the construction of a positive linkage between nuclear energy promotion and climate protection can also serve a different strategic purpose: it can be used to lessen the pressure on states with nuclear-heavy energy mixes to implement climate-related obligations in other (costlier) ways. This strategy is illustrated by the EU’s contested Taxonomy for Sustainable Activities. The European Commission first introduced this regulatory instrument in 2020 as part of the EU’s sustainable finance framework to direct investments to economic activities in line with the ‘European Green Deal’. In 2022, under considerable pressure from nuclear-friendly EU member states (Taskinen Reference Taskinen2021), the Commission proposed an amendment of the taxonomy that re-classified nuclear energy – alongside natural gas – as a transitory energy source that will ‘accelerate the shift (…) towards a climate neutral future’ (European Commission 2022). With this move, it framed nuclear energy investments as guided by the same value as investments into renewable energy sources: mitigating climate change. Through this linkage, it expanded an existing cluster of climate protection norms and enlarged the menu of climate policy options available to member states and private financial actors. Thus, it effectively lessened normative pressure to invest in renewables.

Critics of the taxonomy – including anti-nuclear NGOs such as Greenpeace, the European Green Party and individual member states such as Germany and Austria – opposed the positive linkage between nuclear energy promotion and climate protection as ‘greenwashing’ (European Greens 2021; Greenpeace 2023; Rankin Reference Rankin2022). To challenge it, they discursively re-constructed the connection between nuclear energy promotion and climate change mitigation as a negative one. Austria’s climate action minister, for instance, publicly opposed the inclusion of both gas and nuclear energy into the taxonomy ‘because they are harmful to the climate and the environment and destroy the future of our children’ (cited in Rankin Reference Rankin2022). Greenpeace denounced the ‘fake green label’ as ‘incompatible with EU environment and climate laws’ (Greenpeace 2022). Exemplifying the use of causal claims in the navigation of norm complexity, the group argued that investment in nuclear energy ‘leads to the curtailment of renewables’, while conversely, nuclear power is also a technology ‘heavily impacted by adverse climate events’ (Greenpeace 2023). Such arguments transform the positive linkage of nuclear energy to the climate norm cluster into a negative one: the mitigation of climate change is said to require curtailing, rather than expanding, the use of nuclear power.

In addition to constructing a rival, negative linkage between nuclear energy promotion and climate norms, taxonomy critics also connected the question of nuclear power to normative concerns beyond climate change. The German government, for instance, pointed to the risk of ‘severe accidents with widespread, cross-border and long-term risks to human health and the environment’ to underline its assessment that nuclear energy is not ‘consistent with sustainability objectives’. Rejecting proponents’ central argument, it stated that ‘[l]ow CO2 intensity alone is not sufficient for classification as sustainable’ (Germany 2022 [author’s translation]). In the German Bundestag, Green party representatives also justified opposition to the revised taxonomy by highlighting the ‘danger posed by weapons-grade material if it is spread across the world’ (Deutscher Bundestag 2022: 549 [author’s translation]). This negative linkage constructs nuclear energy promotion as being in tension not only with sustainability and health concerns but also with non-proliferation norms. The latter argument challenges the positive association between non-proliferation and peaceful use of nuclear energy in the NPT ‘norm cluster’ (Lantis and Wunderlich Reference Lantis and Wunderlich2018).

The discursive strategies embraced by governmental and non-governmental opponents of the revised taxonomy illustrate the potential for strategic norm linkage as a low-threshold tool for political activism, which is less demanding than formal forum-shopping strategies.Footnote ⁹ Yet, the eventual failure of these tactics to halt the taxonomy amendment also suggests that the empowering effect of norm linkage had clear limits in the case. In the end, the European Commission and supporting member states prevailed in their linkage strategy: in expanding the menu of climate-friendly finance options beyond renewables, they effectively reduced the taxonomy’s constraining power.

Perspective II: Navigation as cross-cultural encounter

A second perspective on the creative navigation of norm complexity can be derived from a critical approach to norm contestation that emphasizes norms’ fundamental contestedness and the limitations of a rationalist approach to agency. From this perspective, actors connect multiple norms in different ways because their different socialization experiences dispose them to do so.

According to an argument elaborated by Antje Wiener in her critical constructivist theory of norm contestation, actors’ socialization in different normative contexts – their diverging ‘cultural backgrounds’ – constitutes a primary source of contestation over the meanings of global norms in international ‘encounters’ crossing cultural boundaries (Wiener Reference Wiener, Bjola and Kornprobst2010). While Wiener focuses on contestation of individual norms, we can also expect actors socialized in different contexts to bring different interpretations of norm relations to cross-cultural encounters. As scholars of norm localization argue, different cultural contexts are themselves complex normative systems and are marked by local ‘norm hierarchies’ that international norms must be ‘fit’ into (Acharya Reference Acharya2004: 251). If international norms can modify local norm relations, the reverse should also be true: different variants of local embeddedness of a given norm will generate contestation of norm relations in cross-cultural encounters. From this perspective, conflicts over how different international norms relate to one another are driven not by actors’ diverging interests but by their socialization in different – national or transnational – normative systems. Actors draw on their experiences in these systems to connect individual norms in specific ways to a complex global web of norms.

While cross-cultural encounters may lead to convergence on norm relations, it is impossible to determine objectively – from a theoretical viewpoint stressing norms’ fundamentally contested nature – whether the result constitutes a ‘weakening’ or ‘strengthening’ of norms. Similarly, it would be misleading to describe successful contestation as a empowering a ‘manipulator’. However, contestation scholars recognize that power inequalities (Krook and True Reference Krook and True2012: 112–13) and unequal access to contestation (Wiener Reference Wiener2018: 23) may influence contestation outcomes and limit the potential of contestation to enhance the legitimacy of global governance (Wiener Reference Wiener2014: 3).

Applying the second perspective to the conflict over the EU taxonomy both deepens and challenges the strategic linkage perspective on this case.

Deepening the analysis, a critical constructivist reading draws attention to cross-cultural encounters underlying rival constructions of the relationship between nuclear energy and climate change norms. The inclusion of nuclear technology in the EU taxonomy was a success won by a coalition of eleven states, led by France. Opposition to the move was spearheaded by Germany and Austria, two member states governed by coalitions including Green Parties and represented at the time by Green party environmental ministers. Against this background, it appears puzzling that the pro-nuclear coalition included Finland, where the environmental ministry was also headed by a Green party – the Green Alliance party – under the Sanna Marin government (Taskinen Reference Taskinen2021).

For the Green Alliance, Finnish support of the taxonomy amendment was not a concession to its coalition partners, however. Rather, it reflected a general shift toward embracing nuclear energy which had long been advocated by the intra-party group Greens for Science and Technology (GST) and culminated in the party’s 2022 decision to support the expansion of nuclear energy, now labelled as ‘sustainable’ in the party manifesto (Törmänen and Visscher Reference Törmänen and Visscher2022). The shift represented a break with the anti-nuclear stance that had long prevailed among the Finnish Greens. While it was helped by nuclear-friendly attitudes in the wider Finnish society and on the part of previous Finnish governments (Litmanen and Kojo Reference Litmanen and Kojo2011; Törmänen and Visscher Reference Törmänen and Visscher2022), it was not an isolated move limited to Finland or the nuclear field. Rather, it has been embedded in and enabled by a broader set of norms associated with ‘ecomodernism’. This transnational movement, which itself recombines various older tenets of environmental and economic thought (Fremaux and Barry Reference Fremaux, Barry, Biermann and Lövbrand2019), has resonated particularly strongly in Finland and other Nordic countries (Haverkamp Reference Haverkamp2023; Van Der Heijden Reference Van Der Heijden1999). Following the publication of the ‘Ecomodernist manifesto’ in 2015, the Ecomodernist Society of Finland was founded in the same year. Its first chair, Tea Törmänen, joined the Green Alliance Party and GST in 2019 and subsequently played a leading role in bringing about the party’s shift toward embracing nuclear energy, while also lobbying for the inclusion of nuclear energy in the EU taxonomy (Törmänen and Visscher Reference Törmänen and Visscher2022). Simultaneously, Törmänen co-founded and coordinated RePlanet (now WePlanet), an Ecomodernist transnational advocacy network that promotes technology-based solutions to environmental problems ranging from nuclear energy to genetic engineering in agriculture or precision fermentation in food production (Lynas Reference Lynas2023; Thor Reference Thor2022).

In sum, a specific cultural background influenced by both national culture and transnational ecomodernist ideas ‘socialized’ the Finnish Greens into a position on the EU’s nuclear-climate linkage that is diametrically opposed to the majority of the European Greens/EFA alliance. As more green parties inch closer to pro-nuclear stances (Rundle 2023), difficult cross-cultural encounters are likely to continue within the European green party family – and between EU member states.

From a critical constructivist perspective, we can understand the EU’s linkage of nuclear power to climate protection as the outcome of cross-cultural encounters. Unlike the strategic linkage perspective, however, a critical constructivist lens emphasizing norms’ fundamental contestedness would not classify this shift as necessarily ‘weakening’ climate norms, nor understand it as a result of ‘manipulation’ through which political actors gain power over others. However, a critical constructivist perspective does raise the question of how access to contestation is distributed. In the case discussed, the disproportionate access of fossil and nuclear industry lobbyists to EU decision-making on the taxonomy (Plehwe, Neujeffski and Haas Reference Plehwe, Neujeffski, Haas, Brulle, Roberts and Spencer2024: 336) limited the legitimacy-enhancing potential of contestation.

Perspective III: Navigation as complex justification practice

A third perspective on agency in complex normative settings can be grounded in pragmatist analyses of norm-based practices of justification and critique. From this third perspective, actors draw creatively on multiple norms in routine processes of collective agreement-seeking, producing clashes between them but also forging compromises and establishing and contesting moral hierarchies.

While pragmatist IR theory draws on diverse schools of thought, I build here on arguments advanced by Luc Boltanski and Laurent Thévenot and on works applying them to international politics. A core assumption in this strand of theory is that actors act under an ‘imperative to justify’ (Boltanski and Thévenot Reference Boltanski and Thévenot2006: 23; see also Gadinger Reference Gadinger2016; Hanrieder Reference Hanrieder2016; Kornprobst Reference Kornprobst2014; Niemann Reference Niemann2018). This means that they must relate their particular position in a specific situation to universal ‘orders of worth’ – collectively shared evaluative repertoires – to reach agreement within their community and enable collective action (Gadinger Reference Gadinger2016: 6; see also Kornprobst Reference Kornprobst2014: 197–98).

Critically for analyses of norm complexity, pragmatists stress that these repertoires are ‘irreducible’ to one another (Hanrieder Reference Hanrieder2016: 4). This fundamental plurality gives actors creative freedom in deciding under which principles they want to ‘test’ or evaluate a situation (Gadinger Reference Gadinger2016: 5; Lesch Reference Lesch2021: 618–19). Actors have the critical capacity to challenge a political decision by demanding a test under a different order, producing a ‘clash between worlds’ (Boltanski and Thévenot Reference Boltanski and Thévenot2006: 223; see also Gadinger Reference Gadinger2016: 13–16). However, they also have the capacity to ‘suspend’ a clash by avoiding a clarifying test. This produces a situational ‘compromise’, and sometimes a more durable ‘composite’ arrangement – which nevertheless remains open to challenge in new situations (Boltanski and Thévenot Reference Boltanski and Thévenot2006: 277–81; Hanrieder Reference Hanrieder2016: 26).

Pragmatist thought can enrich our understanding of norms in international politics (Gadinger Reference Gadinger2016; McCourt Reference McCourt2016; Pratt Reference Pratt2020). A key contribution lies in highlighting actors’ ‘unavoidably’ creative engagement with norms (Schmidt and Williams Reference Schmidt and Williams2023: 3). Existing pragmatist analyses emphasize this creativity in unpacking the internal complexity and malleability of structures commonly described as single ‘norms’. For instance, they show how agents engage with multiple orders of worth and with multiple principles and practices in interpreting and changing the anti-corruption norm (Lesch Reference Lesch2021) or the prohibition of torture (Pratt Reference Pratt2020). Yet, if we understand internal and external norm complexity as related, as proposed above, the perspective can be extended to studying forms of agency that link different ‘norm’ arrangements in positive or negative ways. From such an extended pragmatist perspective, actors may criticize a specific practice, such as the use of nuclear energy, by producing a clash between guiding values such as security and sustainability that are central to different existing ‘norm’ configurations. Alternatively, they may justify the practice by ‘suspending’ a clash or by merging values from different existing ‘norms’ into a new ‘composite’ arrangement.

To pragmatists, creativity is inherent to routine processes of agreement-seeking within communities, rather than the product of exceptional cross-cultural encounters across community boundaries. Nor does it indicate a strategic manipulation of norms: pragmatists reject the notion that actors ‘seek to invent false pretexts after the fact so as to cover up some secret motive, the way one comes up with an alibi’ (Boltanski and Thévenot Reference Boltanski and Thévenot2006: 37). Consequently, agreements resulting from actors’ creative exchanges should not be seen as strengthening or weakening norms, but as reducing ambivalence and enabling norm-based collective action in situations of uncertainty.

While pragmatists recognize that the outcomes of justificatory exchanges can reflect power relations among political actors, they caution against assuming linear effects. To pragmatists, ‘the invocation of power and authority’ is ‘an argumentative operation that can succeed or fail’ (Hanrieder Reference Hanrieder2011: 410). Conversely, justificatory exchanges can produce hierarchical relations among actors: ‘[O]rders of worth (…) provide the practical devices – cognitive tools, symbols, institutions, and roles – to create and contest moral hierarchies’ (Hanrieder Reference Hanrieder2016: 393). Extending this argument to the study of norm complexity politics, a pragmatist lens draws attention to the invocation of multiple global norms in the contestation of international moral hierarchies.

In applying the third perspective to the nuclear-climate nexus, I focus on two specific justificatory practices: the construction of ‘indivisible objects’ rooted in different normative orders, and the invocation of multiple norms in the contestation of global hierarchies.

A pragmatist analysis of the first justificatory practice deepens our understanding of – government as well as activist – opposition to the positive linkage between nuclear energy and climate change. As pragmatists argue, actors’ creative capacity enables them to produce composite agreements rooted in different ‘worlds’ in processes of collective agreement-seeking. A key justificatory practice to achieve and stabilize such composites is the creation of ‘indivisible objects’:

One such indivisible object is the German concept of Energiewende (energy transition), which merges the exit from fossil fuels – guided by climate protection – with the exit from nuclear energy – guided by public health and environmental concerns – into the overarching vision of a transition towards renewables. Germany was one of the staunchest opponents of the inclusion of nuclear energy in the EU taxonomy. This stance reflected not only the participation of the Green Party in the ruling government coalition during the taxonomy debate, but also a broader political and societal agreement on a specific notion of energy transition. The term Energiewende first emerged in the 1980s. Both the Green party and media used it to refer to calls for a phase-out of nuclear energy, in response to the Chernobyl accident and domestic struggles over nuclear waste (Dernbach Reference Dernbach2015: 26–30). While Energiewende was initially unrelated to climate change, it always combined a nuclear phase-out with a transition to renewables. When climate change came to dominate environmental policy agendas from the 1990s onwards, it consequently became a central point of reference in Energiewende discussions (Hake et al Reference Hake, Fischer, Venghaus and Weckenbrock2015: 537–38). Yet, it was only the 2011 Fukushima nuclear accident and Chancellor Angela Merkel’s subsequent policy shift that led to a (temporary) cross-party consensus on a nuclear phase-out as ‘an essential ingredient of Germany’s Energiewende’ (Hake et al Reference Hake, Fischer, Venghaus and Weckenbrock2015: 543). In 2015, for instance, the German Economic and Energy Ministry explained on its website: ‘“Energiewende,” the energy transition, is Germany’s path to a secure, environmentally friendly and economically successful future. It is the decision to fundamentally reform our energy system: away from nuclear power, towards renewable energy sources.’ (Bundesministerium für Wirtschaft und Energie 2015)

In the German case, collective agreement-seeking produced a composite merging different practices (a nuclear and a fossil phase-out) and guiding values (climate protection, environmental protection and health). As a result, German decision-makers could use the Energiewende concept in 2022 as a justificatory resource against including nuclear energy in the EU taxonomy:

In contrast, recent efforts by members of the Christian Democratic Union and Free Democratic Party to challenge the German Atomausstieg on climate grounds have thus far failed. As Boltanski and Thévenot (Reference Boltanski and Thévenot2006: 279) put it, ‘[w]hen a compromise is worked out, the beings it associates become hard to pry apart’.

The German case exemplifies the emergence and stabilization of a dominant discursive linkage between different evaluative orders through an ‘indivisible object’: the Energiewende concept diminishes opponents’ capacity to articulate alternative energy policy visions.

A different example of creative navigation at the nuclear-climate nexus illustrates how weaker state and non-state actors can introduce a new indivisible object to challenge dominant international discourses and hierarchies. The object analysed here is the construction of nuclear weapons and climate risks as ‘twin threats’ to humanity. The ‘twin threats’ narrative (e.g. Chomsky Reference Chomsky2020) is increasingly used by anti-nuclear organizations to argue against a positive association of nuclear energy and climate change mitigation. As the anti-nuclear organization ICAN contends, ‘[t]he twin concurrent existential threats that confront us, climate disruption and nuclear war, demand win-win solutions. Promotion of nuclear power as a claimed climate friendly energy source is a lose-lose proposition’ (ICAN Australia 2019).

Simultaneously, the ‘twin threats’ narrative is creatively adapted to a different context: state and non-state actors in the Pacific refer to climate change and toxic legacies of nuclear weapons testing as ‘twin existential threats’ to their islands (e.g. Kabua Maddison Reference Kabua Maddison2023). Pacific activists emphasize causal ‘linkages’ and analogies between nuclear testing and climate change, for instance in highlighting the impact of sea-level rise on the safety of nuclear waste sites and the ‘dual displacement’ of populations through both threats (Stünzner Reference Stünzner2024; similarly Kabua Maddison Reference Kabua Maddison2023).

In a pragmatist reading, Pacific actors thus connect normative orders related to nuclear weapons and climate change in international justificatory exchanges about nuclear and climate diplomacy. One aim of this justificatory practice is to win international agreement for financial compensation and support. As a Marshallese activist argues: ‘The humanitarian and socio-economic costs of the nuclear legacy and the climate crisis are insurmountable for a nation without the financial means to mitigate these existential threats’ (Kabua Maddison Reference Kabua Maddison2023).

A further implication is the reconstruction of global moral hierarchies. Pacific leaders connect their experiences of nuclear and climate-related harm to attribute blame and assert moral leadership. For instance, Hilda Heine, President of the Republic of the Marshall Islands, stated at the 2024 UN General Assembly: ‘Our own unique legacy and complex challenges with nuclear testing impacts, with climate change, and other fundamental challenges, informs our perspective, that the voices of the most vulnerable must never be drowned out.’ In the same speech, she emphasized that ‘[w]e did not choose this nuclear fate – it was chosen for us’, and shamed ‘some of the planet’s wealthiest countries’ for breaking their climate pledges in an example of ‘failed leadership’ (Republic of the Marshall Islands 2024). In the communiqué of the 2025 Pacific Islands Forum, Pacific leaders similarly assert their ‘moral leadership’ in nuclear non-proliferation and climate diplomacy based on their specific vulnerability and experiences of harm (Pacific Islands Forum 2025). Meanwhile, Pacific youth activists have coined a new complex term to summarize both claims for moral leadership: they describe their mission as a fight for ‘nuclear and climate justice’ (e.g. Pacific Women Mediators Network 2024).