In the "Ethical Inquiry" series, we examine ethical questions, highlighting a broad array of opinion from journalism, academia, and advocacy organizations. Our intent is to illuminate and explore the complexity of some of the most vexing ethical questions of our time.

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Ethical Inquiry: October 2014


The Ethics of Military Intervention Abroad: When, If Ever, Is It Justified?

The United States has intervened abroad militarily on numerous occasions. In this installment of “Ethical Inquiry” we look at the question of when, if ever, such intervention is justified, as the United States engages in another intervention – the campaign against the Islamic State of Iraq and Syria (ISIS)/ISIL/IS. Our focus will be on the discussion of this issue with regard to actions by the United States.

Justifications for Intervention

There are several arguments that are frequently made in support of military intervention.

International Law

Military intervention abroad is legally justified in Chapter VII of the United Nations Charter. As stated within Article 39 of this intergovernmental charter, the UN Security Council has the ultimate authority of determining “the existence of any threat to the peace, breach of the peace, or act of aggression” as well as in deciding “what measures shall be taken to maintain or restore international peace and security”. Article 51 of the Charter allows a UN member to engage in military action without authorization in cases of self-defense against an armed attack.

When military action overseas is not a self-defense response to a direct attack on U.S. soil, the U.S. has used other justifications.

Just War Theory

Just War Theory is commonly referenced within political discourse as the necessary guidelines for a justified military engagement. St. Augustine first legitimized the act of war as a “necessary evil” that must fulfill the criteria for jus ad bellum (right to war) and jus in bello (laws of war).

Saint Thomas Aquinas further defined jus ad bellum in his “Summa Theologica” by declaring three necessary conditions: a proper authority “of the sovereign by whose command the war is to be waged” and not of a private individual, a just cause “namely that those who are attacked, should be attacked because they deserve it on account of some fault,” and a goal of peace in which the “belligerents should have a rightful intention, so that they intend the advancement of good, or the avoidance of evil.”

The jus in bello laws of war dictate how nations should act once at war to maintain a just core: discrimination is the immunity of non-combatants from direct and intentional harm, while proportionality is that the results of war should not cause more evil that what the aggressor being attacked threatened to cause. (See the Ethical Inquiry “Proportionality in the context of armed conflict,” October 2009.)


The Realist theory that “the basis of international relations is the power struggle among nations which try to maximize their interests,” is used to support the protection of the United States’ hegemonic and military dominance in the world.

During the Cold War, the United States was engaged in proxy wars with the Soviet Union that took place in countries such as Vietnam to protect its economic interests, its military credibility, and its domestic and international political influence against the threat of the Soviet Union’s expansion and the spread of communism.

After the Cold War, this theory continued to be a part of U.S. foreign policy.  Daniel Lieberfeld writes that, “in realist terms,” the U.S. invasion of Iraq in 2003 “was a rational means for the U.S. to achieve its primary goal of demonstrating its power to allies and competitors alike, and of avoiding the appearance of post-9/11 decline.” Further, Iraq’s oil supply and location in the Middle East could provide strategic benefits to the U.S.

Pre-emptive Action

Following the attacks of September 11, 2001, pre-emptive strikes and preventive war gained legitimacy as justifications for military action.

Pre-emptive strikes include actions taken against terrorist organizations to prevent them from actualizing any threats against the United States. Dr. Michael Walzer (Brandeis ’56) of the Princeton Institute for Advanced Study, a prominent Just War theorist, believes that pre-emptive strikes are justified as a response to a “sufficient threat” which he defines as “manifest intent to injure, a degree of active preparation that makes that intent a positive danger, and a general situation in which waiting, or doing nothing greatly magnifies the risk.”

President George W. Bush made the case for this shift in foreign policy during his commencement address to the 2002 graduates of the United States Military Academy at West Point. He contended that a threat from another country or from a terrorist group was sufficient to justify military intervention: “We must take the battle to the enemy, disrupt his plans, and confront the worst threats before they emerge.”

Humanitarian Intervention

J. L. Holzgrefe, co-editor of Humanitarian Intervention: Ethical, Legal and Political Dilemmas, defines humanitarian intervention as "the threat or use of force by a state, or group of states, aimed at preventing or ending widespread and grave violations of fundamental human rights of individuals other than its own citizens, without the permission of the state within whose territory force is applied."

Humanitarian intervention has been cited by the United States as a just and moral reason for military intervention abroad. In 1999, President Clinton released an executive order claiming that Yugoslavia’s ethnic cleansing in Kosovo and de-stabilization of the region was an “unusual and extraordinary threat to the national security and foreign policy of the United States” that justified the U.S.’s involvement in the bombing campaigns in Yugoslavia. The grave crimes against humanity committed in Kosovo of killings, tortures, rapes, and mass displacement were perceived as requiring intervention because they were acts that “shock[ed] the moral conscience of mankind.”

This example of humanitarian intervention, writes Fernando R. Tesón, “gave expression to the moral consensus in the international community that severe tyranny should not be tolerated”, and set a precedent for international organizations and the United States to interfere militarily in other nations’ internal conflicts if heinous crimes were being committed.

In 2014 President Obama referenced humanitarian reasons a rationale for his decision to target ISIS for bombing, including within Syria. Using humanitarian intervention as a justification for U.S. military intervention in Syria, President Obama stated, "When we have the unique capabilities to help avert a massacre, then I believe the United States of America cannot turn a blind eye."

(Note: See the Ethical Inquiry “Is there a Responsibility to Protect?” for an exploration of a related concept.)

Justifications for Non-Intervention

Military intervention abroad is opposed by some on a case-by-case basis, and by others on a more categorical basis. There are several arguments frequently cited in opposition to such intervention.

State Sovereignty

In Human Rights Violations and the Moral Permissibility of Military Intervention, Paul Di Stefano writes, “the principle of non-intervention is firmly rooted in the moral value of self-determination, self-help, and international order." Each nation must respect the ability of other nations to create and sustain their own politics, economies, and societies.

Di Stefano’s statement that "Freedom gained through the paternalistic intervention of outsiders is an ephemeral imposition devoid of lasting intrinsic or instrumental value" suggests that while the U.S. might believe it is bringing freedom and democracy into another country, it is really just setting that country up for failure. Without the culture, institutions, and the will to embrace democracy, it will not naturally become a lasting part of the society.

John Stuart Mill supports the argument for state sovereignty and non-interventionism in “A Few Words on Non-Intervention” first published in 1859. Mill states, “When a people has had the misfortune to be ruled by a government under which the feelings and the virtues needful for maintaining freedom could not develop themselves, it is during an arduous struggle to become free by their own efforts that these feelings and virtues have the best chance of springing up.” Only through a nation’s own efforts can they build a strong and free political community that they are dedicated to maintain.

Does Not Prioritize the Interests of the People Affected

Some contend that the United States ignores the needs and opinions of the people in the countries in which they are intervening, even when the U.S. states that it is intervening for the interests of those people.

For example, some Syrian intellectuals and activists see the U.S.’s military involvement fighting ISIS as detrimental to Syria’s fate, while others strongly support the U.S. action.

Yassin al-Haj Saleh, one of the leading writers and intellectual figures of the Syrian uprising, believes that “an attack against ISIS will send a message to many Syrians (and Iraqis and other Arabs) that this intervention isn’t about seeking justice for heinous crimes, but is rather an attack against those who challenged Western powers. This will lead to more resentment against and suspicion of the outside world, which is the very nihilist mood on which ISIS capitalizes and profits.” His opinion is that military intervention will negatively affect Middle Eastern people’s sentiments towards the U.S. and strengthen ISIS recruitment.

Kassem Eid, a.k.a. Qusai Zakarya, a Syrian-Palestinian activist, “strongly support[s] U.S./NATO air strikes against ISIS,” and “urge[s] the international community to arm the Syrian rebels and provide them with the necessary means to take down ISIS, which has shown nothing but brutality against the Syrian people.”

The Costs of Military Intervention
Some opponents to military intervention point to the human and material costs.

According to the Costs of War Project, the Iraq and Afghanistan wars and the U.S. drone strikes in Pakistan have so far resulted in the death of approximately 220,000 civilians and about 6,800 U.S. soldiers.

Even when soldiers come home from war, they may still be struggling with mental health issues and have trouble re-integrating into society. A recent RAND Corporation study, Invisible Wounds of War: Psychological and Cognitive Injuries, Their Consequences, and Services to Assist Recovery, found that 1 in 5 veterans who had been deployed in Iraq and Afghanistan suffer from post-traumatic stress disorder (PTSD) or major depression.

In addition to the human cost, the budget for these military interventions is estimated to be close to $4.4 trillion US dollars. As of this writing, according to the National Priorities Project, every hour taxpayers in the United States are paying $312,500 for military action against ISIS – which some would argue should be allocated to other needs, both domestic and international.


Some oppose military intervention out of a commitment to pacifism. Pacifism can stem from religious faith, the non-religious belief in the sanctity of life, and the practical belief that war is wasteful and ineffective.

Military intervention can result in the deaths of innocent civilians, the destruction of infrastructure, and the crippling of a sovereign nation. Pacifism promotes “an alternative to the institution of war” with “the establishment of peaceful relationships between states,” and holds that “war and violence are unjustifiable, and that conflicts should be settled in a peaceful way.”

For more on religious perspectives on war and peace, see the Ethical Inquiry “War and Peace: Dilemmas Facing Contemporary Religious Leaders” (March 2011).

Final Thoughts

The ethics of military intervention abroad continue to be hotly debated in the United States, and the perspectives outlined above are only the beginning. Questions include: If it military intervention is permissible, who decides when it is necessary? Which countries are subject to intervention? Which may intervene? If it is not permissible, what alternate approaches are effective and justifiable?

We invite you to continue exploring the ethical issues of military intervention, and to share your thoughts with us on our Facebook page.

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This installment of "Ethical Inquiry" was researched and written by Kristina Jacobs ’15.