Why Regime Character Cannot Alter the Law on the Use of Force

[Dr Saeed Bagheri is Lecturer (Assistant Professor) in International Law at the University of Reading School of Law. His research focuses on the law on the use of force and international humanitarian law]

An Iranian individual traverses the streets of Tehran, with life dictated by meticulous calculation. Words are carefully considered prior to being spoken. Opinions are scrutinised, gestures are moderated, and silences are deliberately curated. Over time, this cautious approach becomes habitual – serving as a strategy for navigating a system in which the boundaries of acceptable expression are neither stable nor transparent. For many, this has long been the reality of residing under a regime that limits fundamental freedoms.

Today, however, an additional layer of uncertainty has arisen. Alongside internal repression, the reality of unlawful external military force has become increasingly salient. Within public debates concerning the employment of force against Iran, a concerning reasoning pattern has arisen, occasionally overtly and sometimes subtly, suggesting that the nature of the Iranian regime could diminish the significance of legal and moral boundaries on force aimed at delegitimising the theocratic regime that aspires to acquire nuclear weapons. Elements of this reasoning are evident in broader critiques of legal restrictions on the use of force, including those associated with the Trump administration, where international law is depicted as excessively restrictive when dealing with adversarial or repressive regimes, as part of the attacking state’s national policy, where there was no evidence of armed attack or imminency of such attack by Iran.

This post advances a clear and limited claim that, under international law governing the use of force (jus ad bellum), the internal character of a regime, however repressive, does not diminish, alter, or otherwise affect the legal constraints on the use of force against it. Crucially, these constraints operate to protect populations as much as to regulate states, and they cannot be relaxed on the basis of a regime’s nature without undermining the principle that civilians are not legitimate objects of force and do not bear responsibility for decisions taken by state authorities.

Internal repression and its legal relevance

The starting point is the state’s internal condition. International human rights law (IHRL) establishes a framework under which individuals are entitled to basic protections, including freedom of expression and assembly, and protection against arbitrary detention. Instruments such as the Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights (ICCPR) articulate these guarantees as universal legal commitments. There is considerable evidence and ongoing reports suggesting that, in Iran, these protections are markedly limited. The repercussions of such limitations extend beyond institutional boundaries; they influence everyday life by affecting communication, social interaction, and relationships with authority. Significantly, they also affect individuals’ ability to engage democratically in political processes and influence governmental decision-making in both internal and foreign affairs. Where political participation is limited and dissent carries risk, the link between the population and the state’s policies becomes attenuated. Decisions concerning foreign policy, e.g., support for non-state armed groups in the region, are concentrated among a relatively narrow set of actors. For ordinary civilians, the ability to shape or contest such decisions is minimal.

This reality is significant in evaluating arguments that implicitly assign responsibility to the Iranian population for their government’s actions by portraying Iran as a “nation of terror and hate”. In contexts of domestic repression, such characterisations are not only morally problematic but analytically flawed, as they presume a level of agency and control among civilians that often does not exist in practice.

An overview of the prohibition on the use of force

The modern law governing the use of force is anchored in Article 2(4) of the United Nations (UN) Charter, which establishes a general prohibition on the threat or use of force in international relations. This prohibition is widely regarded as a cornerstone of the international legal order, and reflects a deliberate effort to move away from a system in which war was treated as a legitimate instrument of state policy. The UN Charter provides only narrow exceptions to this prohibition. Under Article 51, states retain an inherent right of self-defence in response to an armed attack. Additionally, the UN Security Council may authorise the use of force to maintain or restore international peace and security. Outside these frameworks, the use of force is presumptively unlawful and, in its gravest forms, may constitute an act of aggression.

Two structural features of this framework are critical. First, it is state-centric. The legality of the use of force is assessed in relation to the conduct of states – whether an armed attack has occurred or is imminent, whether the self-defence requirements are met, and whether Security Council authorisation exists. The framework does not operate by reference to the perceived moral worth of populations or the internal political character of governments. Second, it is formally indifferent to regime type. The Charter does not distinguish between democratic and authoritarian states in determining the legality of force. Whatever the political system of a state, it is equally protected by the prohibition in Article 2(4), and equally bound by it.

It is noteworthy that these features are not incidental; rather, they are integral to the stability and predictability of the legal order. The introduction of gradations based on regime character would fundamentally modify the structure of the prohibition, thereby risking subjective and potentially opportunistic interpretations.

Regime character as a false justification

It is against this background that contemporary arguments must be assessed. The suggestion that the repressive nature of a regime might justify, excuse, or render more acceptable the use of force against it does not appear in explicit legal form. More often, it operates implicitly – through rhetoric that collapses the distinction between state and society, or that frames entire populations as implicated in the conduct of their governments. At its strongest, this line of reasoning approaches a claim that force directed against a repressive state is at least less problematic – whether legally or morally – than force used against other states. At its weakest, it manifests as reduced sensitivity to the legal prohibition and a readiness to treat the constraints of Article 2(4) as more flexible in certain geopolitical contexts.

Both versions are problematic. From a doctrinal perspective, the UN Charter framework does not admit such distinctions. The legality of force cannot be recalibrated by reference to internal governance without departing from the text and structure of the Charter itself. To accept otherwise would be to reintroduce a form of conditional sovereignty, where the protection of the prohibition depends on the internal political arrangements of the state concerned. From a systemic perspective, such reasoning risks normalising expansive interpretations of the UN Charter and the selective invocation of exceptions. Once the prohibition is treated as contingent on regime character, it becomes vulnerable to strategic interpretation. States may characterise adversaries in ways that justify departures from the rule, thereby weakening its overall force.

Responsibility, agency, and the position of civilians

A fundamental aspect of the prohibition on the use of force pertains to the allocation of responsibility. It designates the pertinent legal actors – primarily, states – and assigns consequences to their decisions to resort to military force. This allocation is crucial for preserving the distinction between decision-makers and those affected by its repercussions. Arguments that depend on a regime’s repressive nature to justify or mitigate the legal evaluation of force risk obscuring this distinction. By referencing the nature of the state in ways that involve the population, these arguments divert attention from decision-makers and focus instead on society at large. This shift is especially problematic in circumstances where the population possesses limited capacity to influence state behaviour. In such instances, the notion that civilians bear any significant responsibility for the state’s external actions becomes difficult to uphold. Nonetheless, it is precisely in these contexts that rhetoric concerning hostile states or regime character is most likely to obscure the separation between the government and the governed.

The result is a conceptual slippage in which the state becomes conflated with its population, and the population, in turn, is implicitly positioned as a relevant factor in assessing the permissibility of force, a move that the UN Charter does not support.

Dual vulnerability in the jus ad bellum framework

The situation of civilians in Iran illustrates a broader structural concern that may be described as one of dual vulnerability. On the one hand, individuals may face internal constraints that limit their rights and restrict their capacity for political participation. These constraints reduce their ability to influence or contest state policies, including those that may lead to international confrontation. On the other hand, these same individuals may be exposed to the risk of external force justified by reference to the conduct or character of the state. In such cases, the very conditions that limit their agency internally are overlooked or discounted in external assessments. This dual vulnerability sharpens, rather than weakens, the case for strict adherence to the prohibition on the use of force. Where populations lack meaningful control over state behaviour, there is an even stronger reason to insist that legal responsibility remains firmly attached to state actors and that the constraints of Article 2(4) are applied without dilution. To argue otherwise is to create a perverse dynamic that the less agency a population has, the more exposed it becomes to the consequences of decisions taken both within and outside its borders.

This is not an argument about defending any particular government. Nor is it an argument about denying the reality of internal repression. It is an argument about maintaining the integrity of a legal rule designed precisely to limit recourse to force in international relations. The prohibition on the use of force is one of the clearest expressions of that effort. Its strength lies in its generality and its resistance to contextual dilution. It applies irrespective of regime type, geopolitical alignment, or strategic convenience. To introduce the character of a regime as a factor that relaxes or reshapes this prohibition is to move away from that clarity. It risks transforming a rule of law into a flexible standard, dependent on political judgment and susceptible to selective application. For civilians living under repressive systems, this shift carries particular significance. They are already situated at a distance from the decisions that shape their state’s external conduct. To allow those decisions – or external reactions to them – to erode the legal constraints on the use of force is to expose them to risks beyond their control.

For the prohibition on the use of force to remain effective both normatively and practically, it must continue to function according to its original principles: holding states accountable, remaining indifferent to regime types, and resisting efforts to treat certain populations as less protected. Only by preserving this structure can international law sustain a credible claim to regulate the resort to force in a manner that protects not only states, but also the individuals who live within them.