Introduction
The Economic Community of West African States (ECOWAS) has evolved into an assertive regional actor in matters of peace, security, and governance. Originally established in 1975 to promote economic integration, ECOWAS began military engagement in 1990 with the launch of the ECOWAS Monitoring Group (ECOMOG) during the Liberian civil war—marking the start of a series of interventions in Sierra Leone, Guinea-Bissau, Côte d’Ivoire, Mali, The Gambia, and, most recently, its threat of force in Niger following the 2023 coup. ECOWAS now positions itself not only as a stabilizing force but also as a guardian of democratic norms in the region. This essay interrogates the legality of ECOWAS’s military enforcement posture under international law, particularly in light of the prohibition on the threat or use of force in Article 2(4) of the United Nations (UN) Charter. It critically examines whether interventions grounded in ad hoc or treaty-based consent, or justified under an emerging doctrine of pro-democratic intervention, can withstand legal scrutiny. In doing so, the essay highlights a growing normative and legal tension between regional democratic imperatives and the universal constraints of the international legal order—raising broader questions about the coherence, hierarchy, and adaptability of international law in a pluralist legal landscape.
Threat or Use of Force: The Ban, the Complexity, and the Exceptions
The prohibition of the threat or use of force is a cornerstone of the post-1945 international legal order, enshrined in Article 2(4) of the UN Charter, and recognized as customary international law.Footnote 1 However, the inclusion in Article 2(4)—“or in any other manner inconsistent with the purposes of the United Nations”—introduced interpretive ambiguity. While some argue this could allow force in defense of democracy or human rights,Footnote 2 the dominant viewFootnote 3 —grounded in International Court of Justice (ICJ) jurisprudenceFootnote 4 —holds that Article 2(4) permits no such unilateral deviation. The rule is considered jus cogens, from which no derogation is permitted. Furthermore, threats of force, if the use itself would be unlawful, are likewise prohibited.Footnote 5
Two exceptions exist: UN Security Council (UNSC) authorization under Chapter VII, and the right of self-defense under Article 51 of the UN Charter. The latter permits defensive force only after an actual armed attack, subject to necessity and proportionality.Footnote 6 Controversy remains over the concepts of anticipatory and pre-emptive self-defense. While some states, notably Israel and the United States, have invoked these doctrines,Footnote 7 including in Israel’s recent aggression against Iran, the prevailing legal opinion—anchored in the Caroline doctrine—requires that self-defense be limited to instances where the necessity is “instant, overwhelming, leaving no choice of means, and no moment for deliberation.”Footnote 8 Valid state consent constitutes another independent legal basis for the use of force—arguably situating such action outside the scope of Article 2(4) of the UN Charter, rather than as an exception to it.
Force by Regional Organizations
Under Chapter VIII of the UN Charter, regional organizations may address disputes within their respective areas,Footnote 9 but their enforcement actions—particularly the use of force—require prior authorization from the UNSC (Article 53). Article 54 requires regional bodies to keep the Council informed.Footnote 10
ECOWAS qualifies as a regional arrangement under Article 52.Footnote 11 While it has played an assertive role in West Africa—including interventions in Liberia, Sierra Leone, The Gambia, and threats in Niger—its legal authority to use force remains limited.
The Charter imposes clear constraints: absent UNSC authorization, any enforcement action must either qualify as lawful self-defense under Article 51 or, alternatively, be based on valid state consent. Otherwise, such interventions violate the jus cogens prohibition of the threat or use of force under Article 2(4). ECOWAS’s legitimacy in military enforcement hinges not on its regional status alone but on strict compliance with the UN Charter’s legal framework governing collective security.
ECOWAS and Forceful Intervention: From Carrot to Stick
ECOWAS’s evolving practice since the 1990s reflects a clear strategic shift—from reactive peacekeeping to more proactive, and at times strong-arm, enforcement of democratic norms. While its earliest interventions, such as in Liberia and Sierra Leone, focused on stabilizing fragile conflict environments— including the first military intervention by a regional body in Africa without prior UN approval,Footnote 12 later operations—most notably The Gambia in 2017Footnote 13 and Niger in 2023Footnote 14 —demonstrate an increasing readiness to deploy or threaten force in response to unconstitutional changes of government.Footnote 15 These cases illustrate ECOWAS’s emerging role as a norm entrepreneur in regional security, challenging conventional legal boundaries under the UN Charter framework.
Indeed, ECOWAS’s approach has evolved from consensus-based diplomacy to a more coercive model—a shift, so to say, to more stick and a little less carrot in dealing with threats to peace and constitutional governance. This transition is illustrated, first, in the move away from a narrow economic integration focus to a robust peace and security mandate; and second, in the shift from peacekeeping and dialogue to the credible deployment—or threat—of force to restore democracy.
The Niger crisis is emblematic of this strategic recalibration. ECOWAS issued a stern ultimatum—warning that, if its demands for restoration of the democratic constitutional order were not met within one week, it would “take all measures necessary to restore constitutional order,” including “the use of force,” directing its Chiefs of Defense Staff to meet immediatelyFootnote 16 — mobilized troops, and declared readiness to intervene militarily;Footnote 17 actions that meet the criteria of a prohibited “threat of force” under Article 2(4) of the UN Charter, as clarified by the ICJ’s Nuclear Weapons advisory opinion. Such threats are unlawful unless the actual use of force would be lawful—i.e., (consent aside), based on UNSC authorization or self-defense. ECOWAS has relied instead on regional norms and treaty obligations, challenging the Charter’s legal limits.
While ECOWAS’s role as a defender of democratic order enjoys political legitimacy, the Niger situation reveals the unresolved legal tension between regional enforcement and the strictures of international law—placing forceful regionalism in a legally precarious position.
Potential Legal Bases for ECOWAS’s Use of Force
Ad Hoc Consent by National Authorities
Under customary international law, foreign military intervention may be lawful if conducted with the valid consent of the territorial state’s government. The ICJ in Nicaragua affirmed that consent by a government in effective control renders the use of force lawful.Footnote 18 Many commentators consider such consent falls outside the scope of Article 2(4) of the UN Charter, arguing that genuine invitation avoids the trigger of the jus cogens prohibition.Footnote 19
However, in cases of internal power struggles or coups, such as in Niger, determining who can issue valid consent becomes complex. President Bazoum, ousted in a military coup, appealed for international assistance,Footnote 20 which could have been considered an invitation for military interventionFootnote 21 —but he no longer exercised effective control. Under classic international law, the authority to invite foreign intervention has traditionally been reserved for a government that holds de facto control over the state’s territory and institutions, irrespective of how that control was acquired. By this standard, Bazoum—having been forcibly displaced and deprived of operational command—would not qualify as a legally competent authority to extend such consent.Footnote 22 Nonetheless, more recent African practice—such as in Sierra Leone (1997) and The Gambia (2017)—suggests a growing acceptance of democratic legitimacy as a criterion for identifying the authority to issue consent.Footnote 23 The UNSC’s July 28, 2023 reference to Bazoum’s government as “legitimate” further supports this view.Footnote 24
Still, the democratic legitimacy test is not universally endorsed. Some insist, minimum effectiveness is necessary to issue valid consent.Footnote 25 Thus, an ECOWAS reliance on Bazoum’s presumed invitation would rest on a contested legal foundation—depending on whether recognition, or control is treated as the decisive element.
Treaty-Based Consent: Intervention Under the ECOWAS Lomé Protocol
ECOWAS may also rely on prior treaty-based consent, particularly Article 25(e) of the 1999 Lomé Protocol, which allows military intervention in cases of unconstitutional changes of government.Footnote 26 Niger ratified this protocol, effectively consenting ex ante to such intervention. A similar clause appears in Article 4(h) of the AU Constitutive Act.Footnote 27
Legal opinion is divided—forFootnote 28 and againstFootnote 29 —such anticipatory consent being valid without contemporaneous confirmation. The Institut de Droit International has suggested that ad hoc confirmation is still required and revocable.Footnote 30 Practice supports this: ECOWAS intervened in The Gambia (2017) only after consent from President-elect Barrow,Footnote 31 and the AU refrained from intervening in Burundi (2015) without such consent or UN authorization.Footnote 32
That said, international law recognizes states’ capacity to bind themselves prospectively.Footnote 33 Unless revoked, treaty-based consent may remain valid.Footnote 34 In the Niger case, whether Bazoum or the junta held the legal authority to revoke consent is a critical question. If Bazoum were considered the legitimate head of state, prior consent under the Lomé Protocol would remain operative. If the junta were treated as the de facto government, opposition to the intervention by the junta could signal a revocation, as the inviting state’s position must be assessed at the time of intervention.Footnote 35 This reveals a legal grey area: can a de facto regime revoke treaty-based consent designed to prevent its own illegitimate seizure of power? One would argue that revocation should be restricted—at least temporarily—in such contexts, to preserve the protective aims of democracy clauses.
This brings Article 103 of the UN Charter into the conversation, as it affirms the primacy of Charter obligations over conflicting treaty commitments. Yet this principle, while foundational, may not be absolute in its implications. Where valid inter-se consent exists—such as through ECOWAS instruments voluntarily acceded to by member states—the use of force does not fall afoul of Article 2(4), because that prohibition presupposes an absence of consent. In such cases, the force is not unlawful ab initio, but can be viewed as lying outside the normative reach of the Charter’s prohibition altogether. This interpretive possibility complicates assumptions about the supremacy of global norms and invites reconsideration of how regional systems with cohesive goals like democracy protection might operate within a pluralist legal order. Rather than viewing regional treaties as inherently subordinate to the Charter, this perspective allows for the coexistence of differentiated legal regimes, so long as the actions they authorize are grounded in genuine state consent and do not violate peremptory norms.
Pro-Democratic Intervention: An Emerging Justification?
A more controversial justification is “pro-democratic intervention,” which posits that force may be used to restore a democratically elected government ousted by unconstitutional meansFootnote 36 —even without consent or UNSC approval. Though not recognized under the UN Charter, the idea gains traction in African practice.Footnote 37
While African regional instruments increasingly support democracy as a core value, reliance on this justification alone remains legally precarious. Unless grounded in ad hoc, and—arguably—prior treaty-based consent, or UNSC authorization, pro-democratic interventions cannot be considered lawful under current international law.Footnote 38 This reflects growing normative tension between non-intervention and emerging democratic solidarity in Africa. This disjunction between regional ambition and global legality reflects a deeper normative challenge: can regional law evolve in ways that contest the boundaries of international law, or must it remain subordinate? ECOWAS’s assertiveness forces a reconsideration of how legal pluralism functions in a nominally universal order.
The Malabo Protocol and the International Criminalization of Unconstitutional Changes of Government
The Malabo Protocol, adopted in 2014, represents a significant normative shift in African international law. It expands the jurisdiction of the African Court of Justice and Human Rights to include international crimes, and it includes the novel crime of “unconstitutional changes of government” (UCGs) in the list of crimes within this jurisdiction. Article 28E, which defines criminal UCGs, lists various acts—including military coups, refusal to cede power after elections, mercenary-backed regime changes, and constitutional manipulation—as international crimes.Footnote 39 This codifies long-standing African commitments, such as in the Lomé Declaration (2000), and African Charter on Democracy, Elections and Governance, translating them into prosecutable offenses.Footnote 40
The Protocol seeks to fill a gap in international criminal law, recognizing that UCGs often precede mass atrocities and regional instability. Yet its efficacy remains constrained. Article 46A bis grants immunity to sitting heads of state and senior state officials, likely undermining accountability, and potential cooperation with other institutions such as the International Criminal Court.Footnote 41 Moreover, the Protocol has not entered into force due to insufficient ratification.
For ECOWAS, the Protocol provides legal reinforcement for its democracy promotion agenda through an alternative channel to military intervention, offering a prosecutorial mechanism that aligns regional enforcement with international criminal accountability. In doing so, it presents a potential pathway to reconcile regional norms with the international legal order—by institutionalizing responses to unconstitutional changes of government within a framework of law, rather than force.
Conclusion
ECOWAS’s evolving posture—marked by the increasing threat or use of force to restore democratic governance—reflects both an innovative and contentious regional experiment. It has positioned itself as a norm entrepreneur in Africa, boldly responding to coups and democratic reversals. Yet this assertiveness tests the boundaries of international law, particularly Article 2(4)’s prohibition on the use of force. While ECOWAS’s military interventions may rest on regional treaty frameworks and prior treaty-based consent, their legality remains uncertain absent UNSC authorization or ad hoc consent from a government in effective control.
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