Constitutional scholarship in a much humbler constitutional world

Both academic analysis and public debate continue to be heavily permeated by inherited conceptions of how constitutions are created and changed. The classic and still influential view, largely inspired by Sieyès, presents a relatively straightforward picture:Footnote ¹ constitution-making is the product of an extraordinary political moment, a rare eruption of the popular will. Constituent power is imagined as non-derived, unbound, and beyond the reach of legal constraints. It gives birth to the constitutional order, under which all subsequent powers are constituted and constrained by law. Within this framework, even the power to amend the constitution, though exercised in contexts more constitutionally significant than ordinary legislation, is nonetheless subordinate to the original ‘sovereign’ constituent power. It remains ‘constituted’ rather than ‘constituent’, and thus constrained by the boundaries established by the constitution.Footnote ² The classic picture takes the shape of a descending hierarchy: the constituent power stands as giant and unassailable; below it, the power to amend the constitution occupies a middle ground – less foundational than the original constituent act yet more consequential than ordinary legislation; activated by high political energy and capable of substantial reform but still constrained by constitutional boundaries; and further down lie the mundane operations of the legislative, executive, and judicial branches.Footnote ³

Yet contemporary realities shatter this picture. On one side, we see what scholars like Andrew Arato describe as ‘post-revolutionary constitutional making’, a process starkly different from the revolutionary paradigm of 18^th-century United States and France (and later Latin America).Footnote ⁴ Unlike the classic model driven by sovereign, omnipotent assemblies, post-revolutionary constitution-making unfolds through elite negotiations, the involvement of international actors, engagement by social movements in dialogue with existing powers, multi-stage deliberations, and intervening judges.Footnote ⁵ Such processes are far removed from the omnipotent, sovereign acts of the old days, both in terms of political momentum and their legal framing, as many non-revolutionary constituent processes are now heavily patterned in legal terms.Footnote ⁶ On the other hand, we know of many constitutional amendment episodes that deviate from their characterisation as energetic and deliberative yet relatively orderly and legally constrained acts in classical theory. Some amendments are as intense and politically charged as full-fledged constituent processes; others disregard established amendment procedures entirely. In some instances, constitutional amendment procedures are almost impossible to distinguish from ordinary legislation; and in still others, amendments produce outcomes so drastic that they might more accurately be described as constitutional ‘dismemberments’ rather than amendments, or amount, in substance if not in name, to the creation of an entirely new constitution.Footnote ⁷

The classic hierarchy – strong constituent power, limited amendment power – may sometimes be completely reversed; far more often, however, it is blurred and reshaped in diverse ways. Occasionally, amendments can surprisingly become a moment of extraordinary democratic engagement, as in Ireland's 2018 referendum to repeal the Eight Amendment, which had prohibited abortion.Footnote ⁸ More commonly, though, contemporary amendment processes are marked by a narrowing or distortion of democratic participation. In countries like Brazil or Mexico, constitutional amendment has been trivialised, reduced to routine political manoeuvring.Footnote ⁹ Meanwhile, in Hungary, Poland, Turkey, and Russia, dominant political actors exploit constitutional amendments with alarming ease to entrench power and reshape institutions.Footnote ¹⁰ The broader trend is clear: constitutional amendments are increasingly converging with ordinary politics and legislation. As Paul Blokker aptly observes, in times of constitutional ‘acceleration’, the constitution increasingly serves as an object of daily political contention, not as a framework for it.Footnote ¹¹ The distinction between constitution-making, amendment, and legislation grows ever smaller and less predictable.

A structural – rather than political – factor helps explain why contemporary constitutional amendment has become more pragmatic and less exalted than traditionally envisioned. Unlike their historical counterparts, modern constitutions frequently include procedural and substantive limits on amendments. This shift has given rise to a new player in constitutional change: the courts, which now engage in judicial review of amendments, whether the constitution explicitly imposes procedural or substantive limits on amendments or not. This judicial intervention is undoubtedly one reason why the amendment process increasingly resembles the back-and-forth between institutions that we commonly associate with everyday politics, contributing to the sense that we now inhabit a much more ‘humble’ constitutional landscape, where constitutions have shed their once sacred aura: instead of enduring as untouchable frameworks, they are now routinely debated, revised, expanded, and even struck down.

How has this shift reshaped the vocabulary and conceptual framework of constitutional scholarship? It would be inaccurate to claim that we still analyse contemporary developments using outdated theoretical tools. At the very least, descriptive analysis has made significant strides. The recent surge in comparative studies on constitutional change has introduced new terminology, more refined analytical categories, and deeper explanatory frameworks. For instance, scholars now differentiate between different modalities of constitution-making – conventional, legislative, participatory, and crowd-sourced.Footnote ¹² We have also developed a detailed taxonomy of amendment processes, classifying them as formal or informal, single or multi-track, and mono- or multi-generational.Footnote ¹³ Beyond conceptual mapping, a burgeoning field of empirical research on constitutional change has emerged.Footnote ¹⁴ Equally notable is the rise of a vibrant debate on the unconstitutionality of constitutional amendments, which has attracted an extraordinary number of scholars. This debate is partly descriptive, documenting the practice in countries like Colombia, Brazil, India, or Hungary, and partly normative, evaluating when the amendment power is used legitimately or illegitimately. In doing so, it grapples with increasingly urgent questions about how to respond to troubling trends in constitutional manipulation and abuse.Footnote ¹⁵

At the normative level, however, the picture remains far less clear. Our traditional vocabulary and frameworks have evolved in some respects while staying constant in others; several things are happening at the same time. On one front, the classic distinction between constituent and amendment power persists, but primarily to reinforce the notion that constituent power cannot be measured against standards of legitimacy, as it continues to be viewed as an expression of sovereign, legally unconstrained authority – though a growing body of scholarship now cautiously identifies, and in limited cases defends, the invalidation of original constitutional provisions.Footnote ¹⁶ On the other front, regarding amendment power, two divergent trends have emerged: (1) a deferential approach, which largely accepts amendments as legitimate exercises of political authority; and (2) a scrutinising approach, which subjects amendments to judicial review and entertains the possibility of declaring them unconstitutional.

The first is exemplified by what Lael Weis terms ‘popular-sovereignty-based theories of constitutional amendment’, which view amendments – like the original constitution – as a product of the popular will.Footnote ¹⁷ Scholars diverge, however, on how the popular will manifests in this framework. ‘Popular constitutionalists’, in the words of Weis, argue that the popular will emerges outside the amendment procedures; ‘formalists’, by contrast, locate the emergence of the popular will within the legally prescribed amendment process.Footnote ¹⁸ Joel Colón-Ríos, who exemplifies the formalist approach, grounds the constitution's normative authority in whether its formal amendment procedures preserve the constituent power.Footnote ¹⁹ Conversely, Bruce Ackerman's reconstruction of US constitutional practice aligns with the popular constitutionalist view.Footnote ²⁰

In either manifestation, popular-sovereignty-based theories offer little basis for constraining amendment power. Once we recognise an authentic expression of ‘We the People’ making an amendment, the question of legitimacy has answered itself once the proper subject has spoken – by definition, in a democracy amendments derive their validity from their sovereign source, the people. When the amending subject is inherently legitimate by definition, the crucial theoretical task would not be to distinguish between legitimate and illegitimate amendments, but rather to develop criteria for identifying authentic expressions of ‘We the People’.

Despite their theoretical appeal, I will set aside popular-sovereignty-based theories in this analysis for three reasons. First, they build on assumptions that have grown increasingly implausible in our contemporary ‘humble’ constitutional landscape that is characterised by pragmatism rather than romanticised popular will. Second, these theories become particularly dangerous in an era of populist governance, where authoritarian leaders routinely claim exclusive embodiment of ‘the People's’ voice. Third, and most importantly, such theories fail on both descriptive and normative grounds. They strain credulity when applied to today's accelerated, often cynical amendment processes, and by offering virtually no framework for evaluating amendment limits, they provide no meaningful standard to assess the legal and constitutional battles that increasingly threaten democracy's foundational conditions.

A defender of popular-sovereignty-based theories might counter that today's often cynical amendment processes do not genuinely reflect the People's will. But this merely shifts the debate to a circular question: What truly counts as an authentic expression of popular sovereignty? This theoretical pivot proves doubly problematic. For scholars, it obscures rather than illuminates the crucial issues – namely, how to evaluate the legitimacy, correctness, and validity of specific constitutional changes. For real-world politics, where academic concepts are increasingly weaponised to validate political moves,Footnote ²¹ it provides perfect cover for authoritarian populists. Leaders like Donald Trump, Viktor Orbán, Boris Johnson, López Obrador, and Narendra Modi routinely position themselves as the true voice of the people – an especially powerful claim when attempting to alter constitutions drafted decades ago by bodies that fail to meet modern standards of democratic inclusivity. This perceived historical illegitimacy becomes a convenient pretext for claiming a more ‘authentic’ representation of the will of the people, thereby justifying even the most undemocratic constitutional changes under the mantle of popular legitimacy. In other words, when every amendment can potentially claim popular legitimacy simply by asserting it, we lose all meaningful criteria to challenge constitutional changes.

The second trend in normative amendment theory – the scrutinising approach – takes the opposite view. It contends that legitimate amendments must strictly adhere to constitutional limitations. This approach maintains that amendments, both procedurally and substantively, cannot cause the amended constitution to deviate significantly from its original form. This concept has gained remarkable traction in theory and practice, achieving a dominance comparable to the once-prevailing notion that ‘an unconstitutional constitution’ represented a logical contradiction.Footnote ²² Its ascendance has coincided with the global expansion of judicial review of constitutional amendments and the widespread adoption of the doctrine of unconstitutional constitutional amendments – even in jurisdictions whose constitutions lack explicit amendment restrictions, as implicit limits are often found to exist. As Richard Albert aptly describes it, this has become ‘the conventional theory of constitutional change’.Footnote ²³

This second framework places the legitimacy of constitutional amendments at the heart of the discourse, intrinsically connected to analyses of constitutionality and unconstitutionality. I will now examine the merits and limitations of anchoring legitimacy assessments around this concept – operating within what I term a standard of internal amendment legitimacy.

Why the unconstitutional constitutional amendment doctrine is not enough

The increasing recognition of procedural and substantive limitations on constitutional amendments in positive law has given rise to the unconstitutional constitutional amendment (UCA) doctrine, which contributes to blur the line between legality and legitimacy.Footnote ²⁴

The UCA doctrine, advanced in varying forms by courts and scholars, posits that amendments may be unconstitutional on two grounds: procedural violations (failure to follow the constitution's prescribed amendment process) and substantive violations (contravening what the constitution designates as unamendable). However, courts and scholars have articulated divergent, often sophisticated interpretations of what the constitution designates as unamendable. The clearest manifestation of this doctrine occurs when constitutions explicitly declare certain principles, concepts, or institutions to be unamendable, such as the ‘eternity clauses’ found in the constitutions of Germany, Portugal, Brazil, Turkey, and Greece. Beyond such express limitations, courts have also implicitly inferred an unamendable constitutional core from the broader structure or identity of a constitution. This includes prohibitions against altering the basic structure of the constitution (India), compromising the constitutional identity (Germany), and attempts at wholesale ‘substitution’ of a constitution with a new constitutional order (Colombia).

Indeed, the Colombian Constitutional Court has famously held that the power to amend the constitution is limited to amending the constitution, not substituting it with an entirely different one. The Court has framed this distinction as a matter of procedural, not substantive, validity – assuming, in Kelsenian parlance, that a legal rule is valid only if enacted by an authority with legally established jurisdiction, following the legally prescribed procedure. At the same time, the Court has articulated specific criteria for distinguishing amendment from substitution, which inevitably require a degree of substantive analysis. Scholars, too, have often invoked the concept of unconstitutional constitutional amendments when addressing what David Landau terms ‘abusive constitutionalism’, the strategic use of formally impeccable constitutional amendments to erode commitments, rules, or institutions that are critical for the preservation of constitutional democracy.Footnote ²⁵ In this way, the doctrine has become a critical analytical tool for understanding and resisting the growing trend of undermining democracy and constitutionalism from within – using their own tools – and for examining the judicial strategies developed to safeguard constitutionalism in the face of such challenges.

As Oran Doyle aptly observes, the doctrine ultimately holds that amendments that are morally and conceptually unconstitutional must be treated as invalid no less than those that are formally unconstitutional.Footnote ²⁶ If procedural review of amendments, which effectively distinguishes legitimate amending authorities from usurpers, is widely accepted and persuasive, why should extending this logic to the substantive realm pose any difficulty? After all, substantive review is necessary to draw a line between what falls within the scope of the amendment power and what belongs exclusively to the constituent power, and many courts around the world have done just that in recent years. Nor can such substantive review be dismissed as improper judicial moralising. Constitutional frameworks have, for decades, incorporated moral considerations into their own structural boundaries, not least because the very logic of fundamental rights jurisprudence demands it. In other words, substantive review is not based on subjective ethics, but on foundational principles that are presupposed by the constitutional order itself.

Yet in an era of populist constitutionalism and authoritarian legalism, the UCA doctrine – despite its moral and conceptual advances – faces new complexities and limitations. While the debate over its strengths and weaknesses is hardly new,Footnote ²⁷ certain challenges have become especially pressing in light of the populist capture of constitutions and courts. I argue that the central challenge today is not that the doctrine has become too powerful, but that it is not powerful enough. Three key limitations emerge: first, the authoritarian corruption of constitutional texts; second, the co-optation of the judiciary by authoritarian regimes; and third, broader shifts in law's relationship with morality.

The first limitation stems from the doctrine's reliance on the distinction between the formal and the ‘material’ (or ‘real’) constitution. This distinction typically draws on a variant of Carl Schmitt's conceptual framework, which defines the constitution as a set of fundamental political decisions – what Schmitt termed the ‘positive’ concept of the constitution.Footnote ²⁸ These fundamental decisions are often described in terms such as the constitution's ‘identity’, ‘basic structure’, or ‘essence’ – that which must remain intact to avoid substitution by an entirely different constitutional order. Unfortunately, as Schmitt's own historical influence illustrates, this framework is dangerously pliable: it can be mobilised just as easily to dismantle a constitution as to defend it. It is neutral regarding what constitutes ‘fundamental decisions’ or constitutional identity. Consider Hungary as an example. Had the Hungarian Constitutional Court applied Schmitt's reasoning to the 1989 amendments to the constitution, it could have invalidated them for destroying the Soviet-inspired 1946 Constitution. By the same token, the doctrine could now be invoked to argue that the 2011 amendments illegitimately altered Hungary's constitutional identity.Footnote ²⁹

The content-neutrality of the Schmittian-inflected version of the UCA doctrine has functioned reasonably well in recent years, particularly against the backdrop of constitutions with a broadly liberal-democratic character. The pressing question now is what happens when courts invoke this doctrine to uphold and enforce constitutions that have already been reshaped by illiberal, inegalitarian, or antidemocratic amendments – changes that, for various reasons, have not been invalidated or purged by judicial review. While courts and scholars have traditionally favoured democracy-preserving interpretations of constitutional identity, in times of democratic regression, this same concept may lead toward entirely different outcomes. Yaniv Roznai and Tamar Hostovsky Brandes have observed that the UCA doctrine proves ineffective against the gradual erosion characteristic of authoritarian legalism and the creeping rise of illiberal constitutionalism – unless it is applied holistically through what they term ‘aggregated review’. Such an approach requires shifting focus away from isolated constitutional amendments and toward the cumulative impact of changes over time.Footnote ³⁰ They also argue that, to effectively combat contemporary abusive constitutionalism, the doctrine may need to be extended beyond amendments to encompass ‘constitutional replacements’.Footnote ³¹ Yet even the aggregated approach may fail in cases where constitutional transformation is, for the longest time, too incremental or subtle to meet the threshold of an illiberal ‘replacement’. This reveals a fundamental limitation of the UCA doctrine: once constitutional damage has become sufficiently entrenched to warrant the doctrine's application, courts may paradoxically find themselves bound to uphold the authority of a constitution that is already profoundly compromised.

The UCA doctrine's second major limitation is its vulnerability to judicial manipulation, with few safeguards against such abuse. Critics have highlighted this weakness as creating a ‘super counter-majoritarian difficulty’: by empowering courts to block constitutional amendments, it might also foreclose the political branches’ ability to respond to judicial interpretations through amendment.Footnote ³² More generally, the challenge lies in the doctrine's reliance on abstract, high-stakes interpretations. Courts applying the UCA doctrine must grapple with inherently indeterminate concepts: democracy, federalism, the rule of law, and constitutional identity. Though interpretation of indeterminate principles is not unique to the UCA context and also arises in ordinary judicial review, the interpretive leeway is considerably greater for principles of such a foundational nature. Indeed, some scholars have suggested that international or transnational legal frameworks could serve as ‘anchors’ to guide and constrain the interpretation, thereby reducing the risk that judges simply substitute their own moral or political convictions for constitutional imperatives.Footnote ³³ Yet even when drawing on international and transnational frameworks, the potential for judicial ‘reconstruction’ remains vast – particularly in jurisdictions with older, fragmented, or heavily amended constitutions, which may be burdened by internal contradictions. In such cases, judges face competing historical interpretations and possibly contradictory constitutional provisions that have accumulated over time, which creates opportunities for selective citation of historical precedents that support a judge's preferred outcome, rendering the application of the UCA doctrine almost boundless.

The pressing question, then, is what should be done once neo-authoritarian populists have gained access to state institutions and begun to co-opt, weaken, or pack the judiciary. In practice, the UCA doctrine has often been effective in curbing such leaders’ efforts to dismantle constitutional constraints on public power. Yet there is reason to fear that, as courts are increasingly stacked with loyalists – judges more committed to enabling authoritarianism than defending constitutional principles – the doctrine that once protected democracy becomes a tool to legitimise its dismantling.Footnote ³⁴ Several Latin American countries already illustrate how executive-aligned judges can invoke the UCA doctrine in ways that ultimately undermine foundational constitutional principles.Footnote ³⁵ And the strategic appointments of ideologically aligned judges by leaders like Recep Tayyip Erdoğan, Donald Trump, Viktor Orbán, and Evo Morales suggest a troubling trajectory for the doctrine's future efficacy.

The third and final limitation of the UCA doctrine lies in its tendency – across its various formulations, whether based on constitutional identity, basic structure, or the ‘material’ constitution – to avoid direct engagement with moral reasoning. While it does engage with moral considerations (at least when moving beyond purely procedural constraints), the doctrine's effectiveness relies on filtering moral arguments through a severely restricted conceptual framework: terms like ‘constitutional amendment’, ‘constitutional replacement’, and ‘constitutional identity’, among a few others, become the sole vehicles for deeper normative debate. To be sure, all moral reasoning in constitutional law is mediated, insofar as it must ultimately translate into public, rather than private, justifications.Footnote ³⁶ However, the UCA doctrine imposes a distinctly more restrictive, secondary limitation on normative considerations. It requires that all potentially relevant moral arguments be painstakingly compressed and reframed as either an assault on the constitution's essential core or as a moral or conceptual subversion of the very idea of the constitution.Footnote ³⁷

In stable democratic periods, grounding political discourse within constitutional parameters effectively promotes public reasoning and channels diverse perspectives into a collective dialogue about constitutional meaning. But in periods of neo-authoritarian resurgence, this approach risks trapping us in ever-narrowing boundaries of permissible contestation. As constitutions themselves become political battlegrounds rather than enduring normative frameworks for political action, relying on constitutional fundamentals as the foundation for assessing the legitimacy of our collective arrangements may prove both ineffective and self-defeating. The liberal-democratic constitutions of the post-war period – many of them deliberately receptive to international and transnational developments – have historically provided robust platforms for comprehensive legitimacy assessments. While this continues to be the case in many jurisdictions, an alarming number of constitutional systems now fail to offer such a capacious normative framework.

In short, the UCA doctrine faces a paradoxical fate: it is becoming increasingly overcharged and increasingly ineffectual. Much is asked of it. While it remains a compelling idea in theory and has, at times, delivered promising results in practice, its success is highly contingent on the character of the court that applies it and the nature of the constitution it seeks to protect. When weaponised by captured courts or applied to flawed constitutional structures, the doctrine, albeit designed to safeguard democracy, can instead accelerate its erosion. It also carries a subtler cost: it risks obscuring or neutralising the difficult but essential debates about constitutional legitimacy that a political community must be willing to face head-on.

Greater clarity about the legitimacy of constitutional amendments is therefore necessary beyond a technical refinement of the UCA doctrine: we need a richer vocabulary of legitimacy to evaluate constitutional amendments. The UCA doctrine's great strength lies in its invocation of arguments of internal legitimacy – arguments that draw authority from within the legal system itself, speaking in the name of the constitution. This gives it a rhetorical and institutional power that few arguments of external legitimacy can match. To say that a measure ‘destroys the constitution’ or ‘is not a valid amendment’ resonates far more forcefully than any abstract appeal to democratic values or justice. Yet this raises a crucial question: How can arguments that do not originate within the constitution – or even within the legal system – claim a legitimate place in debates about the legitimacy of constitutional amendments? In what ways, in which fora, and under what conditions can external considerations become relevant? And, perhaps most importantly, what exactly are considerations that lie outside the law but still bear on the legitimacy of constitutional amendment?

Four dimensions of self-standing external legitimacy

Self-standing, external arguments about amendment legitimacy are arguments that do not depend on principles explicitly or implicitly derived from the constitution itself or from other para-constitutional sources of higher law, such as international human rights treaties. These latter sources represent what I refer to as standards of internal legitimacy – they derive their authority from within the framework of a particular legal order, no matter how broadly that order is defined. External standards of legitimacy, by contrast, rely on normative or evaluative criteria that must, of course, be publicly justifiable. These standards are fundamentally moral rather than legal, meaning they do not derive their force from positive law. However, they are not based on particular morality codes, but appeal to self-standing standards of correction that are moral in nature.

Of course, identifying these external criteria will not be without controversy, and neither will be their operationalisation. This is evident from the rich academic debate that has emerged in recent years around a different application of the internal/external distinction – one not focused on legitimacy but on performance (ie, standards for evaluating constitutional success and failure).Footnote ³⁸ Tom Ginsburg and Aziz Huq, for instance, distinguish between internal and external criteria for assessing constitutional performance. They define internal criteria as those rooted in the specific context of a given constitution or the political community it governs, whereas external criteria are conceived as generalisable or universal across some or even all countries.Footnote ³⁹ They specifically focus on four external dimensions: (1) the extent to which constitutions function as sources of legitimacy; (2) their effectiveness in channelling political conflict; (3) their capacity to reduce principal-agent problems in representative democracy; and (4) their ability to create structures for the provision of public goods and to solve collective action problems.Footnote ⁴⁰ Building on and engaging with Ginsburg and Huq's framework, Rosalind Dixon and Theunis Roux – together with a team of contributors – identify four broad thematic areas for evaluating constitutional performance: (1) democratic constitutionalism and constitution-making; (2) rule of law, corruption, and accountability; (3) gender justice; and (4) race, poverty, and social and economic transformation.Footnote ⁴¹

As the overlaps and divergences between these two approaches suggest, what counts as ‘external’ to the law can take many forms. the context of assessing constitutional performance, Dixon and Roux underscore the inherent interdependence between internal and external criteria. ‘Internal criteria for assessment’, they note, ‘will themselves be notoriously difficult to identify in any meaningful or objective way’,Footnote ⁴² while ‘the way in which we construct our understanding of “external” constitutional purposes is often deeply informed by the scope and practices – or internal goals – of actual constitutional systems’.Footnote ⁴³ Ultimately, Dixon and Roux argue that the aims we ascribe to constitutions are largely the product of a complex dialogue between national, international, and transnational legal spheres.Footnote ⁴⁴

The idea of a ‘transnational anchoring’ is indeed a notion proposed by Rosalind Dixon and David Landau in the debate on constitutional amendment, offering a framework to prevent the judiciary from misusing its powers when assessing the constitutionality of constitutional amendments. According to them, when courts must safeguard a constitutional democracy's core against abusive amendment practices, reference to a body of shared principles and practices emerging from contemporary comparative constitutional practice can serve as a valuable guide.Footnote ⁴⁵

Useful and reasonable as these proposals are, we must situate our discussion within broader conceptual boundaries. First, the focus here is not on performance (success or failure) but on legitimacy – a more demanding evaluative standard than mere effectiveness or functionality. We must preserve the space to ponder whether a pattern of constitutional amendment (or a constitutional system) is legitimate or illegitimate, even if we cannot classify it as ‘failure’ in terms of its performance. Normative legitimacy is more than just success. Second, we should not confine the criteria for amendment legitimacy solely to transnational anchoring. As I have argued, transnational practice is likely to lose its persuasive force in the coming years, especially after the erosion caused by the recent wave of neo-authoritarianism. Rather than retroactively deriving democratic principles from a compromised transnational consensus, we may need to collectively reimagine and reconstruct the core tenets of constitutional democracy.

With these nuances and caveats in mind, and fully acknowledging that any external standard of judgment invites reasonable disagreement, I propose four dimensions that are, in my view, immediately relevant to guide the discourse on external legitimacy: (1) legitimacy of origin, (2) legitimacy of procedure, (3) legitimacy of content, and (4) legitimacy of justification. In other words: an amendment may be illegitimate due to (1) normative deficits of the authority or agent that brings it to life, (2) normative deficits in its process of adoption, (3) normative deficits in the substance of its provisions, or (4) because the necessity and advisability of the amendment have not been adequately justified.

The legitimacy of origin is the first dimension of external legitimacy that we might naturally invoke to assess the varying degrees of normative legitimacy in amendment practice. It concerns the agents involved and the composition of the body or bodies responsible for enacting the amendment, as well as the circumstances surrounding its adoption. As in assessing the legitimacy of constitutional assemblies, the inclusiveness of the amending body – whether in terms of gender, race, class, ethnicity, or regional representation – matters; so does whether the members are selected through rigorous electoral procedures or through flawed, possibly fraudulent procedures; and it also matters whether an amendment arises from a sincere desire to adapt the constitution to new social realities or to correct its problematic aspects, or whether it is driven by manipulative or abusive efforts to maintain power or undermine the public interest. When the amendment process involves multiple agents, issues of legitimacy of origin will inevitably arise in relation to each of them, with their effects complementing or reinforcing one another. Most of these considerations would not be relevant from an internal legitimacy perspective (which focuses only on the agents prescribed by the amendment formula) and would not be grounds for declaring the amendment illegal, unconstitutional, or void. However, they are central to the broader debate on when amendments lack or possess moral legitimacy. This debate is concerned with the institutional, political, and social factors that influence the consideration, adoption, or rejection of amendments.

The second dimension of external legitimacy, procedural legitimacy, concerns, as the term suggests, the decision-making process that brings an amendment to life. Elements such as the breadth and diversity of participants, voting rules, voting rounds, cooling-off periods, prior consultations, and the use of referendums all shape the quality and character of the collective deliberation. The full spectrum of criteria typically employed to assess decision-making procedures in constitutional democracies can also be applied to evaluate the legitimacy of amendment processes. In the domain of amendment scholarship, some more specific proposals have been advanced. Yaniv Roznai, for instance, has suggested that that the closer an amendment process resembles a constituent process, the more reason there is to accord it deferenceFootnote ⁴⁶ – noting that the constituent process meets a certain threshold of deliberative and inclusive features that amendment processes should also include. However, this may not be said of non-revolutionary constitution-making, which is often marked by elite negotiation, external imposition, and narrow, non-deliberative debate. The idea of deliberative and inclusive constituent processes may also not hold true for constituent processes that are too revolutionary: while they may be legitimate under the doctrine of sovereign constituent power, they offer little guidance for evaluating procedural quality in ordinary, non-revolutionary amendment contexts. When viewed through the far more expansive lens of external legitimacy, the challenge is not to find a single procedural model to emulate, but to articulate reasonable standards of procedural evaluation drawn from a wide and diverse range of possible institutional designs and historical experiences.

The third dimension of external legitimacy, legitimacy of content, asks whether an amendment is substantively legitimate. An amendment may be deemed illegitimate if its content conflicts with widely held ideas about how a political community should be justly organised, such as by eradicating judicial independence, criminalising political dissent, entrenching systemic inequalities, and establishing state religion. It is crucial to create space for evaluating the legitimacy of constitutional amendments from this substantive perspective – not solely through the language of rights, but by encouraging a richer and more pluralistic culture of constitutional critique. This includes engaging with diverse normative frameworks rooted in constitutionalism, democratic principles, and social transformation. An important methodological choice arises here: At what level should content-based legitimacy be assessed? One option is to adopt an ‘independent’ theory, which evaluates the legitimacy of each amendment in isolation. Another is to apply a ‘satellite’ theory, where amendments are judged based on their cumulative impact on the constitution's overall legitimacy. The latter approach reflects what Roznai and Hostovsky term ‘aggregative review’ – used particularly as a strategy that adapts the UCA doctrine from an internal legitimacy perspective to more effectively counter populist threats.Footnote ⁴⁷

Seen through the lens of content legitimacy, an individual amendment may be considered legitimate in one context but illegitimate in another. Take, for example, mandatory retirement at a certain age: in some cases, this can be entirely unproblematic – or even beneficial – as it encourages renewal of ideas within institutions and increases equality of opportunity for groups previously under-represented or excluded. Yet, in other contexts, such measures can be deeply problematic. In countries like Poland and Hungary, for instance, forced retirements have been used strategically to purge independent judges and replace them with partisan loyalists.Footnote ⁴⁸ This is where satellite theories of amendment legitimacy become particularly useful. They are well-suited to situations where the legitimacy of an amendment depends not just on its content in isolation, but on the broader pattern it forms part of – especially when a series of amendments collectively serve to advance a particular political or legal agenda.

Finally, a compelling yet largely unexplored approach to constitutional amendment legitimacy centres on justification – the idea that a constitutional amendment can only be legitimate if it is adequately justified. This perspective extends to constitutional amendments the justificatory requirements increasingly applied to ordinary exercises of public authority. As a large body of scholarship has shown, the global expansion of democratic constitutionalism – characterised by the direct judicial enforceability of rights – has precipitated a global shift from legal ‘cultures of authority’ to legal ‘cultures of justification’. Moshe Cohen-Eliya and Iddo Porat capture this shift in a stylised contrast. As they remark, in a culture of authority ‘the legality and legitimacy of government action is derived from the fact that the author is authorized to act’, so that ‘public law … focuses on delimiting the borders of public action and on ensuring that decisions are made only by those authorized to take them’.Footnote ⁴⁹ In a culture of justification, by contrast, ‘the existence of authority to act is a necessary but insufficient condition for legitimacy and legality; instead, the crucial requirement for legitimate and legal government action is that is justified in terms of cogency and persuasiveness, that is, its rationality and reasonableness’.Footnote ⁵⁰

Requiring substantive justification for constitutional amendments would mark a fundamental reorientation of constitutional politics, shifting authority from the mythologised, almost sacral realm of sovereign constituent power to the deliberative processes of ordinary democratic governance. In today's humbler constitutional landscape, the normative framework for evaluating amendment dynamics must evolve to reflect contemporary realities. As the aura of majesty fades, so too does the presumption of deference, making it all the more reasonable to require that the power to amend be exercised with clear and substantive justification. In practice, this would mean that amendments must be accompanied by explicit, public reasoning in their favour. But what kind of arguments would such justification entail? Intriguingly, a justification-based approach can serve as a standard of both external and internal legitimacy – it can be used by courts when reviewing amendments, but it can also anchor a broader public discourse beyond the courtroom. The nature of appropriate justification may differ across these contexts, but its necessity in both cannot be denied.

In the context of judicial review of legislation, the requirement of justification is typically operationalised through proportionality analysis. When applied in ordinary law, proportionality demands that public authorities or private actors demonstrate that measures infringing upon rights pursue constitutionally significant objectives, and that such measures are suitable, necessary, and appropriate. Absent this justification, such measures are not viewed as legitimate limitations of rights, but as violations of them.Footnote ⁵¹ This raises a compelling question: what would the requirement of justification entail if applied by courts to evaluate the internal legitimacy of constitutional amendments, irrespective of subject matter? What analytical parameters would guide such a review? Could proportionality be adapted to this context, obliging amending authorities to articulate a constitutionally coherent objective and to show that the reform is suitable, necessary, and strictly proportionate – without causing disproportional harm to the existing constitution relative to the goals pursued? Would this impose an unduly conservative standard for determining the legitimacy of amendments, potentially stifling constitutional evolution? How would this approach differ from the application of the basic structure doctrine? And finally, what remedy would be appropriate in cases where formal justification is provided, but proves substantively inadequate or defective?

In public, non-judicial practices of independent amendment evaluation, it is more appropriate to rely on forms of justification distinct from judicial proportionality analysis. While still demanding that amending authorities offer reasoned arguments in support of proposed constitutional changes, these justifications would likely draw on a broader array of normative and empirical considerations. They would need to demonstrate the necessity, advisability, and constitutional desirability of the amendments, and could be integrated with other strands of external assessment – origin, procedure, and content, invoked separately or in combination. In the realm of public debate, the expectation that authorities offer reasons is ever-present. Sometimes, it may suffice to affirm or critique the circumstances surrounding the amendment's genesis, its procedural regularity, or its substantive content. At other times, a more encompassing debate about the concatenation of normative, empirical, and social factors may be necessary to either justify and thereby legitimise the amendments, or to expose their deficiencies and prove them illegitimate.

Expanding practices of contestation in different contexts

To foster greater accountability in contemporary constitutional amendment practices, it is essential to cultivate greater public scrutiny and collective deliberation. This requires creating and reinforcing spaces for critical engagement beyond the judiciary – such as in the media, on social networks, in citizen assemblies and town halls, political forums, and universities. In these venues, people should begin to assess amendment processes on their own terms, through independent and reasoned reflection, something we have largely lost the habit of doing, due to the pervasive and deeply embedded influence of contemporary constitutional positive normativity. In these alternative spaces, debates should flexibly consider how amendments are adopted, by whom, for what reasons, and based on what empirical evidence. Crucially, this should be done without being constrained by the rigid binary of whether a change qualifies as an ‘amendment’, thereby opening space for more nuanced and substantive forms of democratic evaluation.

This does not mean UCA doctrines and other judicially enforceable standards rooted in core constitutional principles no longer have a role to play. Yaniv Roznai is correct in pointing out that recent global events demonstrate that leaving these issues ‘solely for the public arena without judicial involvement [ie, in the realms of law of the public rather than public law] is not always enough’.Footnote ⁵² Moreover, as he equally remarks, legitimacy talk, unrelated to legality talk, carries its own risks: legitimacy is inherently more subjective, varying across persons, places, and times, and as such it can potentially undermine the rule of law.Footnote ⁵³

Yet again, given the limitations of constitutional texts and apex courts as guardians of contemporary democracies, it may be increasingly important to move beyond the comfort zone of politically neutral constitutional arguments and supplement (not replace) constitutional arguments with direct moral evaluations of political and legal developments, regardless of what constitutions explicitly state. Especially as citizens and scholars, we should engage more actively in the public moral assessment of constitutional amendments. Drawing on the constitutional thought of Hannah Arendt, Agnihotri reminds us that constitutional meaning and authority are ultimately shaped and sustained through both formal and informal channels. The constitution, in this view, is a living site of contestation, continuously reshaped by the everyday political actions of ordinary citizens.Footnote ⁵⁴ This is why, in her account, the legitimacy of constitutional amendments cannot be fully determined by any single institution, including the judiciary.Footnote ⁵⁵ Of course, in times of populism, faith in civic participation may be fragile, and one may hold political ideals that diverge from Arendt's republican ethos. Still, civic engagement remains a crucial resource in the ongoing effort to reimagine and reconstitute democratic life. Making this engagement more visible in how we describe and interpret constitutional interactions may be a modest but meaningful first step toward realising its transformative potential.

There are two types of contexts in which an expanded practice of public contestation around constitutional amendments would be particularly valuable. The first involves countries where the amendment process remains exclusively under the control of the political branches, because courts have chosen not to exercise constitutional review over amendments – regardless of whether the constitution includes explicit limits on constitutional change, as in Norway, or does not, as in Mexico.Footnote ⁵⁶ The second context arises where political actors increasingly misuse or exploit amendment mechanisms, even while formally complying with procedural and substantive requirements. These are the kinds of situations where, as Yaniv Roznai memorably puts it, the amendment ‘is kosher but it stinks’.Footnote ⁵⁷

Consider Mexico as an example of the first type of case. As I mentioned in the introduction, the country is currently trapped in a swirl of unending amendment.Footnote ⁵⁸ While it is not surprising that a 107-year-old constitution (which contains no unamendable clauses) requires periodic updates, the steady stream of reforms is driven less by constitutional necessity than by the political incentives of negotiating amendments, compounded by structural factors.Footnote ⁵⁹ The pattern has enormous political and legal costs. Amendments are usually adopted in package with legislative proposals, negotiated behind closed doors and adopted with minimal deliberation. The result is a constantly shifting, increasingly incoherent constitutional text. This not only hampers judicial enforcement and the cultivation of a robust constitutional culture, but also fails to address underlying agency problems or provide a stable framework of reference.Footnote ⁶⁰ Clearly, there is an urgent need to introduce checks on the current dynamics of constitutional amendment.

The Mexican Supreme Court, however, has declined to scrutinise the frequency of constitutional amendments, citing reasons ranging from the formal inadequacy of existing review mechanisms to appeals to the superior status of the ‘permanent constitution-maker’ (ie, the amendment power).Footnote ⁶¹ This reluctance is, to some extent, understandable, given the challenges such review would pose. Procedural review, while theoretically desirable, is hindered by the lack of detailed procedural requirements in the Mexican Constitution. As a result, the Court would face a difficult choice: either adopt a deferential stance that leaves entrenched political practices untouched, or take a more assertive approach that could lead to the widespread invalidation of amendments. Substantive review is arguably even more pressing, especially as new amendments increasingly introduce provisions that conflict with human rights standards. However, attempting to define the constitution's identity or core structure – or finding a stable basis for distinguishing between reform and substitution – on the foundation of a text now laden with layers of historical amendments seems almost impossible.Footnote ⁶² For instance, should the core of the Mexican Constitution be identified with provisions declaring that all property belongs to the nation, or with those regulating private property?Footnote ⁶³ Should the essentials be found in the sections of the bill of rights that embrace international human rights law, or in those that restrict freedom of expression, the presumption of innocence, voting rights, and personal liberty?Footnote ⁶⁴

In sum, the amendment dynamics in Mexico diverge radically from the idealised models found in classical constitutional theory. Attempting to assess their legitimacy strictly within the confines of the existing constitutional framework would require immense effort – and may still fail to address the root causes of dysfunction. This is especially true given that the Mexican Supreme Court does not even offer a forum for such debates in the first place. Engaging public opinion and legal analysis in a broader, more open-ended practice that demands justification for amendments and openly calls out the routine shortcomings and opportunism that characterise the contemporary amendment process would, arguably, contribute better to improving constitutional culture and accountability.

Mexico is an example where external legitimacy discourse becomes especially valuable, precisely because there is no established tradition of internal legitimacy review by the courts. Another scenario where such external scrutiny is vital arises when internal legitimacy debates do exist but fail to capture the full range of relevant developments – particularly in cases where amendments are legal but seem illegitimate, or illegal but seem legitimate. The ‘legal but illegitimate’ category corresponds to Roznai's concept of constitutional fraud or misuse. As he illustrates with examples drawn from recent political events in Israel and elsewhere, the examples include contain reforms that are legal in three senses: they were enacted according to the prescribed procedure; they do not violate unamendable provisions or other explicit limitations; and they respect the basic structure and identity of the constitution.Footnote ⁶⁵ Nevertheless, they conceal motives that undermine the spirits of their constitutions, even if they successfully mask them.Footnote ⁶⁶ On the basis of an exploration of the main purposes of modern constitutions, Roznai identifies several instances of illegitimate amendment misuse: partisan, non-consensual, or extreme majoritarian amendments; hasty and undeliberated amendments; temporary and ad hoc amendments; self-serving amendments enacted for private, not public interest; and amendments that undermine electoral competitiveness and fairness or dismantle individual or minority rights.Footnote ⁶⁷ While Roznai identifies a few courts that have already invalidated these manipulative episodes, their efforts would be far more effective when paired with broad practices of ‘external’ contestation. While the general public may not always articulate arguments in judicial terms, they often recognise when an amendment is little more than a blatant power grab, an attack on political opponents, or a bid for private advantage. Public criticism and demands for justification may not always stop these episodes, but they can raise the political stakes and help safeguard constitutional integrity.

A case that may fall into the category of ‘illegal but legitimate’ can be found in Belgium. The country's constitutional amendment procedure is extraordinarily demanding: it requires the dissolution of Parliament after a formal decision to open certain provisions to amendment, followed by deliberation by the newly elected Parliament and a supermajority vote. Despite this demanding process, there have been instances of questionable legality.Footnote ⁶⁸ As Toon Moonen recounts, for a period, the Belgian Parliament resorted to the practice of ‘implicit’ amendments – indirect alterations to the meaning of certain constitutional provisions through changes made to others.Footnote ⁶⁹ Although this practice was eventually discontinued following the 1993 Fourth State Reform, and many voices criticised it as dangerous and unconstitutional, Moonen notes that the political response remained ambivalent. The practice was not openly endorsed, but neither was it clearly condemned – suggesting that its perceived legitimacy, at least from a political standpoint, remained intact.

A comparable dynamic unfolded with the emergence of a second phenomenon: the ‘temporary amendment procedure’ introduced during Belgium's Sixth State reform in 2012. This time, the amendment formula itself (Article 195) was listed among the provisions to be amended. The newly elected Parliament introduced a one-time, temporary provision that opened the door for the amendment of numerous additional articles that had not been formally opened to revision.Footnote ⁷⁰ While Moonen categorises this episode as an example of a ‘legal but illegitimate’ amendment, what stands out, in my view, is the sheer difficulty of applying any definitive label. On one hand, although Article 195 was properly opened for amendment, the change it underwent appears to subvert the spirit of the amendment rules: it was tailored to facilitate a specific reform episode and introduced sunset provisions, which runs counter to the idea that amendment rules constitute a stable, durable framework, to be revised only sparingly and prospectively. On the other hand, many of the articles forming the core of the Sixth State Reform had not been formally opened to amendment, seemingly violating procedural requirements. Yet the reforms were broadly seen as necessary and legitimate by key actors – including the government, political elites, the Venice Commission (an independent advisory body of the Council of Europe on constitutional matters), Constitutional Court judges, significant segments of the legal academy, and arguably, the wider public.Footnote ⁷¹ All of them could have arguably grounded their support for the amendments in normative, ultimately moral, arguments regarding the substantive value and corrective nature of the reforms.

The Belgian case suggests that a strengthened practice of contestation, based on considerations that go beyond the parameters set by amendment procedures or explicit and implicit limits, does not always dilute the social legitimacy or acceptance of amendments (in a Weberian sense) and can contribute to outcomes that are normatively defensible and broadly accepted. This more holistic form of public debate can cut both ways: it can delegitimise amendment efforts that would otherwise pass unchallenged, and it can bolster the social acceptance of reforms that might appear procedurally questionable but substantively justifiable. But more importantly, if it is reasonably inclusive – plural and unmanipulated – it can enrich judicial reasoning where courts are active, or provide an essential forum for constitutional reflection in jurisdictions where judicial review is weak or absent.