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Humanitarian Intervention

  1. Terry Nardin

Published Online: 1 FEB 2013

DOI: 10.1002/9781444367072.wbiee119

The International Encyclopedia of Ethics

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Nardin, T. 2013. Humanitarian Intervention. The International Encyclopedia of Ethics. .

Publication History

  1. Published Online: 1 FEB 2013

What should be done when a massacre or similar atrocity occurs in a country other than one's own? The thought that the governments of other countries should halt the atrocity, using force if necessary, yields the doctrine of humanitarian intervention. The moral rationale underlying that doctrine is not hard to grasp. When human lives are threatened by violence, those who are able to rescue the victims and to resist the violence should intervene, if they can do so without imposing disproportionate costs and by morally permissible means (see Violence). The rationale is strongest when violence rises to the level of “crimes against humanity,” an expression adopted for the trial of German leaders at Nuremberg in 1945 to cover degrading, large-scale violence by a government against its own people (see Crimes Against Humanity). Because it is in tension with the idea of state sovereignty, humanitarian intervention has an insecure place in international law and is problematic on practical grounds as well, but that tension has only fueled debate on the circumstances in which forcible interference by one state in the territory of another is justified to prevent such crimes.

The moral principle underlying humanitarian intervention is that coercion is justified to resist unjustified coercion (see Coercion). To coerce others is to use or threaten force to get them to do something they would not otherwise choose to do. Human beings are creatures capable of making choices and they are entitled to make choices for themselves. Call this “independence.” One person cannot legitimately make choices for another without the latter's consent, except in roles such as that of a parent or trustee. Each is therefore morally required to respect the independence of everyone else. But if a person's independent choice is obstructed by unjustified coercive interference, that interference can be resisted, whether by that person directly or indirectly by someone acting on his or her behalf. The principle can also be stated in the language of rights (see Rights). Each person has a right to independence and other persons are forbidden to act in any manner that violates that right. If they do, the violation may be resisted. Except when it responds to unjustified coercive interference, coercion is forbidden because it unjustifiably interferes with the right to independence properly claimed by every human being.

In civil society, the right to coerce is assigned to government, for government is supposed to enact and enforce laws that protect the independence of its members. But an individual may also justifiably resort to coercion in certain situations, even in civil society, to resist an interference that violates his or her right to independence. To resist violence against oneself is “self-defense” (see Self-Defense). To resist it on behalf of someone else is to “intervene” in the relationship between violator and victim. Such intervention is justified to obstruct the violator's unjustified infringement of the right to independence and so to protect the victim. Coercion is permitted when it is used to resist violence against oneself or others. It is not permitted when it is used to resist morally justified coercion.

The idea of humanitarian intervention extends this reasoning to relationships between states, understood as legally organized communities. A state is presumed, as an artificial or legal person, to have a right to independence that is analogous but not identical to that of a natural person. That right is not what Kant would call “innate” or natural but rather is “acquired” by a state, on its establishment, by derivation from the innate rights of the natural persons who are its members (1996 [1797]: 393). Each state has a presumptive right to independence – in the vocabulary of international law, to political sovereignty and territorial integrity – which means not only that it can defend that independence (see Just Cause (in War)) but also that it is obligated to respect the independence of every other state. States must therefore refrain from coercively interfering in each other's internal affairs (however defined). The rule that forbids coercive interference in matters within the jurisdiction of a state is called “the nonintervention rule.” Arguments for humanitarian intervention justify it as an exception to that rule. The idea of intervention presupposes a rule-governed international order in which each state has a right to independence. It acquires that right as a member of a society of states constituted and regulated by international law. One state can “intervene” in the internal affairs of another only if there are rules that distinguish internal affairs from those that are external. A world without states would have no nonintervention rule to override and therefore no possibility of intervention.

International lawyers are at odds on the legality of humanitarian intervention. On the one hand, the United Nations Charter and many treaties explicitly prohibit coercive interference by one state in the internal affairs of another. On the other, there is evidence that the international community recognizes humanitarian intervention as a lawful exception to the nonintervention rule in certain situations. The Constitutive Act of the African Union, for example, permits the Union to intervene if necessary to protect human rights in member states, and the idea that the Security Council can authorize intervention when human rights violations constitute a threat to peace has now become entrenched in UN resolutions and practice. In addition, some legal scholars argue that humanitarian intervention is increasingly, if still uncertainly, becoming part of customary international law (Stromseth 2003). To the extent that it forbids intervention to protect human rights, international law departs from generally accepted principles of morally permissible coercion, resulting in a tension between morality and law.

This tension is evident when we contrast twentieth-century international law, which is based largely on treaties and which reiterates the nonintervention rule, with international law (though it is anachronistic to call it that) in the European sixteenth and seventeenth centuries. That law was based on custom (ius gentium or “the law of nations”) and moral principle (“the law of nature”), though these bodies of law were often confused with one another. Grotius and other influential writers on international affairs of that period argued that rulers were justified in using armed force to punish wrongdoing, including crimes committed by other rulers against their own subjects (Grotius 1925 [1646]: 504–6; Muldoon 2006). The absence of a clear distinction between customary and natural law explains the openness of these writers to what was later called humanitarian intervention (see Natural Law; Just War Theory, History of). Today, international law (which includes the nonintervention rule) is again under pressure from morality, under the banner of human rights, with renewed calls to enforce those rights against governments that fail to uphold them.

Personal morality cannot simply be transferred to relations between states, however. The “morality of states,” as it might be called, must recognize the acquired right of governments to make and apply laws, and that means recognizing that laws cannot precisely correspond to moral principles. In particular, the morality of states necessarily permits states to govern themselves, as a consequence of their acquired right of independence, and therefore recognizes a limit to intervention even when governments violate the rights of subjects or allow those rights to be violated. That is why intervention is usually regarded as justified only in cases of widespread and atrocious human rights abuse: massacre, enslavement, deportation, and the like.

It is sometimes objected, against this view, that if one can intervene to prevent large-scale atrocities, one should be able to intervene to prevent small-scale ones as well. Wrongs are wrongs wherever they occur, and national boundaries should not be an obstacle to dealing with them. There are two responses to this “cosmopolitan” criticism of the morality of states (see Cosmopolitanism; International Relations). The first is that intervention is impractical and disproportionate as a way of dealing with scattered human rights abuses. Only widespread and extreme abuse can justify military action, which imposes costs of its own. Practical considerations may therefore lead one to avoid the use of force even when the moral arguments for using it are otherwise strong (see Proportionality (in War)). The second is that the abuses may fall below the line dividing internal matters from matters of international concern – especially concern at a level that could justify military action. A rule that allowed military intervention whenever wrongs were committed in another state would be one that effectively denied political communities the right to manage their own affairs. Humanitarian intervention in situations where the wrongs do not rise to the level of crimes against humanity is therefore unjustified not only on practical grounds but also in principle because it would wrongly infringe the independence that normally, and properly, belongs to any community organized as a state. The morally justified presumption against coercive intervention involves tolerating some moral wrongs, though that presumption is overridden if the wrongs are sufficiently grave. The nonintervention rule is morally justified because it protects the acquired right of a political community to make its own choices. Advocating intervention whenever those choices are morally objectionable is not only impractical but denies states the independence to which within broad limits they are morally entitled. Hence the conclusion that a state forfeits its right to independence, and therefore its immunity to intervention, only when its infringement of the rights of its people is extreme.

The adjective “humanitarian,” though routinely used to describe interventions to obstruct violence, is unfortunate because it has connotations that can confuse the debate. It implies that a state's motive for intervening must be charity or benevolence. This in turn invites the claim that interventions are never humanitarian because states intervene only for reasons of self-interest, not out of genuine humanitarian concern. One might respond by observing that an intervention that ends a massacre can be morally justified, regardless of the motives (which must be various) of those who make the decision to intervene. Humanitarian intervention is grounded not only on beneficence but also on considerations of justice, and this means that acting on any motive is permissible because justice is concerned with actions, not motives.

The word humanitarian also obscures the distinction between providing aid with the consent of the receiving state, which does not involve coercive interference, and military intervention, which does. It implies that any situation in which people need aid is one in which other states may justifiably intervene. But, some argue, that principle is too permissive. Although a country that is poor or has suffered a natural disaster is one that other countries should assist, states may not intervene militarily to provide such assistance. They cannot intervene even when a government is tyrannical, corrupt, or undemocratic. What annuls a state's claim to immunity from intervention is not its character but its acts: the graver its crimes, the less it can justifiably claim immunity under the nonintervention rule. Intervention is justified by a government's crimes, not its illegitimacy. The purpose of a military intervention must be to stop an ongoing or imminent massacre or other crime against humanity. Using military force to remove an undemocratic regime aims at revolution, not rescue or prevention of a crime against humanity, and is not “humanitarian intervention” in the usual sense of that term (Nardin 2005: 22).

Regime change is not an end compatible with either international law or the moral principles on which it is based, which recognize the independence of states and the concomitant right to organize political life in ways that differ from those of liberal Western democracies. One must distinguish between Iraq in 2003, whose regime was undemocratic and oppressive (but not more so than those of many other countries), and Rwanda in 1994, in which about 20 percent of the population died in a few months of genocidal violence (see Genocide). Intervention in Rwanda was morally justified, given the scale of the massacre and the participation of government armed forces and government-supported militias. The war against Iraq was different. Once the reasons advanced for invading (to end Iraq's support of al-Qaeda and deprive Iraq of nuclear weapons) had been discredited as mistaken, if not disingenuous, apologists for the war sought to rationalize it as a humanitarian intervention intended to remove a tyrant and establish a democracy. It is the regime's illegitimacy, not its conduct, that bears the justificatory weight in their argument.

Those who disagree with this conclusion argue that the external legitimacy of a state should be judged according to the same criteria as its internal legitimacy. The state has a responsibility to protect the human rights of its subjects, and the authority of its government is justified because it is necessary for that government to discharge that responsibility. If it fails to discharge it adequately, there are no moral grounds on which one can object to intervention by other states to remedy the failure (Altman and Wellman 2009: 100). But this argument links internal and external legitimacy so tightly together as to leave little room for reasonable disagreement on the definition of human rights or the measure of adequate respect for such rights in circumstances of religious, moral, legal, political, and economic diversity. The debate illustrates a division in liberal thought between those who would limit coercive interference to dealing with extreme human rights abuses (Walzer 1977) and those who think that it is justified at least in principle whenever the practices of a society diverge from the prescriptions of a liberal view of human rights (Buchanan 2004). The nonintervention rule modified by an exception for crimes against humanity establishes a threshold that a more permissive rule would merely shift, not erase. Disagreement over how much diversity is tolerable, and therefore where the threshold for coercive intervention should be set, is inevitable. Even if such disagreement could be resolved in principle, the practical problem of judging when that threshold had been crossed in a particular case would remain.

Until recently, the debate over humanitarian intervention was focused on the permissibility of intervention. But one can also consider the permissibility of a state's not intervening to prevent violence. There is such a principle governing interpersonal relations, or so some moralists hold: “If one person is able to save another and does not save him, he transgresses the commandment, Neither shalt thou stand idly by the blood of thy neighbor” (Donagan 1977: 86, quoting the medieval Jewish theologian Maimonides, who in turn quotes Leviticus). Whatever these words might once have meant in their various contexts, they are taken by those concerned with humanitarian intervention to mean that when crimes against humanity occur, governments that can rescue the victims and prevent further violence have a duty to do so (see Duty and Obligation). The idea of such a duty is evident in the expression “responsibility to protect,” which has become part of international discourse in the context of UN diplomacy (Evans 2009). As articulated in UN documents such as the 2005 World Summit Outcome (UNGA A/60/L.1 2005) and a subsequent report of the Secretary-General (UNGA A/63/677 2009), each state has a responsibility to protect those it governs against crimes against humanity. If it fails to do so, that responsibility passes to the international community, which may resort to armed intervention if voluntary measures are ineffective. But the Security Council must authorize such intervention; there is no provision for unilateral action outside the framework of the UN Charter, which bars unauthorized military intervention.

The reason for insisting on authorization is to prevent abuse of a principle that legitimizes the use of force by states. Military intervention must be authorized by the international community acting in its collective legal capacity, which at the moment means within the framework of international law and, specifically, Chapters V to VIII of the UN Charter. These provisions establish the authority of the Security Council to act when there is a threat to peace and they are now often read as applying to civil as well as international conflicts. As a legal principle, the authorization requirement makes sense (and has long been part of just war theory), but it does not answer the moral question of what duties or responsibilities a state might have when the UN is unable to act for political or other reasons. Morally speaking, it might be argued that if the international community as represented by the UN is unable to act, the duty to intervene devolves upon states acting unilaterally. “Unilateral” action in this context means acting without UN authorization; several states may act jointly yet still be said to act unilaterally in this sense, as NATO members did when they bombed Serbia to suppress ethnic violence in Kosovo in 1999. Since the UN did not perform its duty to protect, NATO moved in to assume it.

It is sometimes argued that it is not clear which states have a duty to act in such situations. The duty is “imperfect” in the sense that there is no particular agent whose performance of the duty can be demanded as a matter of right, and against whom a claim of wrongdoing could be brought for not performing it (see Imperfect Duties). Someone should intervene but it is not clear who bears the duty to do so (Tan 2006: 97–102). Among the proposed solutions to this problem of agency is the suggestion that the duty falls on states that have a special relationship with the target state or possess the requisite military capability. But there is a sense, however, in which the agent is specified and the duty therefore perfect: the duty falls on the international community collectively and on its members individually. If the community is not organized to make collective decisions, what is missing is not an agent but a representative that can act on behalf of its members. Since agents are in fact identified (each state is an agent), the duty is not imperfect: all states have a duty to resist violence, and even if they are unable to intervene in a particular case, they must, at a minimum, work to establish a representative through which they can respond adequately to it. If a representative exists, as is arguably the case since the founding of the UN, they have a duty to ensure that it performs its responsibilities. If it does not, they have a duty to act unilaterally in its absence. Just as the international community assumes the duty to protect when the government of a state fails to discharge it, so other states have a duty to protect unilaterally when the international community as a whole, acting through the UN, fails to perform its responsibilities.

Another point of contention is whether humanitarian intervention is a duty of beneficence or justice. If the duty to intervene rests on beneficence, it is an imperfect duty (even when there is a specific agent or representative) because it lacks a criterion of satisfaction. A duty of beneficence does not prescribe a specific kind of act, as in the case of a duty to repay a loan. It is a duty to promote the welfare of others that allows the agent wide discretion in choosing how to perform it. If beneficence is the ground of humanitarian intervention, states can decide how much or what kind of assistance they will provide. But if justice is the ground, only resisting the violent can discharge the duty. Intervening to stop a massacre differs from providing relief after a hurricane or earthquake, where the principle of beneficence calls for action but does not prescribe the amount of relief to be provided. The correct position is probably that humanitarian intervention rests not only on the principle of beneficence but also, and more importantly, on the duty to coercively obstruct the wrongdoer (Bagnoli 2006: 127–30). The latter is a duty of justice, not beneficence. If one can prevent violence, to stand aside while it is being done is to fail to perform the duty to resist injustice, thereby accepting the injustice as well as forsaking the victims. Governments have a duty to suppress violence not only to protect the victims but also to enforce the law and uphold the principle that violence is intolerable.

It might be objected that international law can be “enforced” only by a proper authority, not by states acting in the absence of Security Council authorization. The government of a state has authority over its citizens but it has no authority within the jurisdiction of other states. But it can also be argued, against this view, that the UN is a voluntary union of states within international society, not the embodiment of that society. If international law exists outside the UN, states can enforce it without UN authorization. There is also a nonlegal sense of the word “enforce” according to which it is intelligible to say that a state that acts to end a massacre enforces respect for human rights, in addition to protecting those whose rights have been violated. This ordinary, nonlegal use of the word reflects the reality of an international order in which the authority of the UN remains limited, contested, and uncertain.

A different objection is that humanitarian intervention violates the rights of citizens of the intervening state. When a government intervenes to protect the rights of foreigners, it expends funds it has acquired by taxing its citizens and it exposes its soldiers to risks of injury and death. In doing so, it violates their rights by forcing them to spend money and even their lives for the benefit of foreigners. If a state exists to protect its members, incurring costs to protect the members of other states violates the social contract. One might respond by arguing that intervention can benefit the citizens of the intervening state, and that it is justified when those benefits outweigh the costs. But that utilitarian response is beside the point because the objection is framed in terms of rights. One would need to show that the rights of citizens are not violated by policies that benefit foreigners. One way to do this is to argue that citizens can be compelled to bear the costs of enforcing human rights abroad as well as at home, but they cannot be compelled to bear those costs when there is no duty on the part of their government to intervene. Where there is such a duty, the state may tax its citizens or assign them for military duty to perform it (Dobos 2010). If the ultimate justification for using force is not self-defense but defense of the innocent, there is no relevant distinction on which such an objection can rest.

Drawing out the implications of the discourse on humanitarian intervention, one can hold that states have a duty to resist crimes against humanity. At a minimum, they have a duty to cooperate in an authoritative regime of international law that can effectively prevent such crimes. They also have a duty to act unilaterally when that regime has broken down, either by intervening directly or by supporting intervention by other states. And if the duty to resist violence is a duty of justice as well as of beneficence, it would not be wrong for an international authority, should one emerge, to requisition forces or levy taxes to maintain a protective force as the representative of the members of international society. Enforcing laws that forbid violence, or that require cooperation to prevent it, does not violate anyone's moral rights. If instead of viewing humanitarian intervention in relation to the victim of violence we view it in relation to the perpetrator, it is clear that the duty to intervene rests on a responsibility to defend civil order against the rule of violence.

There is disagreement about how much responsibility a state assumes when it intervenes militarily. If a state intervenes to thwart a massacre, it must be able to show that a massacre was under way or imminent and that the use of force was necessary to prevent it (see Preventive and Preemptive War). If a state intervenes but withdraws too soon, its intervention may fail to alter the conditions that produced the violence or to prevent its recurrence. But is it reasonable to hold that the duty to intervene is also a duty to take responsibility for security and welfare in a state until a just and stable order has been secured? Intervening to halt a massacre is only one of many measures that might be necessary to restore order and prevent further violence. Appreciating this fact, moral philosophers have followed policymakers in moving the debate from remedial intervention to prevention. It is a move, however, that takes us beyond the topic of humanitarian intervention to larger questions of international and global politics.


  1. Top of page
  2. References
  3. Further Readings
  • Altman, Andrew, and Christopher Heath Wellman 2009. A Liberal Theory of International Justice. Oxford: Oxford University Press.
  • Bagnoli, Carla 2006. Humanitarian Intervention as a Perfect Duty: A Kantian Argument, in Terry Nardin and Melissa S. Williams (eds.), Humanitarian Intervention. New York: New York University Press, pp. 11740.
  • Buchanan, Allen 2004. Justice, Legitimacy, and Self-Determination: Moral Foundations for International Law. Oxford: Oxford University Press.
  • Dobos, Ned 2010. “ On Altruistic War and National Responsibility: Justifying Humanitarian Intervention to Soldiers and Taxpayers,” Ethical Theory and Moral Practice, vol. 13, pp. 1931.
  • Donagan, Alan 1977. The Theory of Morality. Chicago: University of Chicago Press.
  • Evans, Gareth 2009. The Responsibility to Protect: Ending Mass Atrocity Crimes Once and for All. Washington, DC: Brookings Institution Press.
  • Grotius, Hugo 1925 [1646]. The Law of War and Peace, trans. Francis W. Kelsey. New York: Oxford University Press.
  • Kant, Immanuel 1996 [1797]. The Metaphysics of Morals, in Mary J. Gregor (ed. and trans.), Practical Philosophy. Cambridge: Cambridge University Press, pp. 353603.
  • Muldoon, James 2006. “ Francisco De Vitoria and Humanitarian Intervention,” Journal of Military Ethics, vol. 5, pp. 12843.
  • Nardin, Terry 2005. “ Humanitarian Imperialism,” Ethics and International Affairs, vol. 19, pp. 216.
  • Stromseth, Jane 2003. Rethinking Humanitarian Intervention: The Case for Incremental Change, in J. L. Holzgrefe and Robert O. Keohane (eds.), Humanitarian Intervention: Ethical, Legal, and Political Dilemmas. Cambridge: Cambridge University Press, pp. 23272.
  • Tan, Kok-Chor 2006. The Duty to Protect, in Terry Nardin and Melissa S. Williams (eds.), Humanitarian Intervention. New York: New York University Press, pp. 84116.
  • Walzer, Michael 1977. Just and Unjust Wars: A Moral Argument with Historical Illustrations. New York: Basic Books.

Further Readings

  1. Top of page
  2. References
  3. Further Readings
  • Arbour, Louise 2008. “ The Responsibility to Protect as a Duty of Care in International Law and Practice,” Review of International Studies, vol. 34, pp. 44558.
  • Davidovic, Jovana 2008. “ Are Humanitarian Military Interventions Obligatory?Journal of Applied Philosophy, vol. 25, pp. 13444.
  • Gomes, Bjorn 2011. “ The Duty to Oppose Violence: Humanitarian Intervention as a Question for Political Philosophy,” Review of International Studies, vol. 37, pp. 104567.
  • Holzgrefe, J. L., and Robert O. Keohane (eds.) 2003. Humanitarian Intervention: Ethical, Legal, and Political Dilemmas. Cambridge: Cambridge University Press.
  • Lang, Anthony F., Jr. (ed.) 2003. Just Intervention. Washington, DC: Georgetown University Press.
  • Nardin, Terry 2009. The Moral Basis of Humanitarian Intervention, in Joel H. Rosenthal and Christian Barry (eds.), Ethics and International Affairs: A Reader, 3rd ed. Washington, DC: Georgetown University Press, pp. 85101.
  • Nardin, Terry, and Melissa S. Williams (eds.) 2006. Humanitarian Intervention (Nomos 47). New York: New York University Press.
  • Orwin, Clifford 2006. “ Humanitarian Military Intervention: Wars for the End of History?Social Philosophy and Policy, vol. 23, pp. 196217.
  • Roff, Heather M. 2010. “ Kantian Provisional Duties,” Jahrbuch für Recht und Ethik/Annual Review for Law and Ethics, vol. 18, pp. 130.
  • Roth, Kenneth 2006. “ Was the Iraq War a Humanitarian Intervention?Journal of Military Ethics, vol. 5, pp. 8492.
  • Walzer, Michael 1980. “ The Moral Standing of States: A Response to Four Critics,” Philosophy and Public Affairs, vol. 9, pp. 20929.
  • Weiss, Thomas G. 2007. Humanitarian Intervention: Ideas in Action. Cambridge: Polity.