Abstract
With the end of the Cold War, United States presidents have shown growing disinterest in complying with the United Nations Charter prohibition on the use of force. Their legal advisers have based justifications for resort to military force on ever thinner legal grounds to the point that justifications appear to focus only on the legal principles governing the conduct of military force, not on the right to resort to force in the first instance. Samuel Moyn captured the phenomenon in his book, Humane: How the United States Abandoned Peace and Reinvented War. The phenomenon of decline has not stopped with the prohibition of force, however. It has continued, reaching the law on the conduct of force. Legal advisers since 9/11 have provided thinner and thinner arguments on the conduct of force, now at the vanishing point as well. The arguments try to justify using military force outside armed conflict zones to conduct targeted killings of terrorism suspects, reprisal attacks to “send a message,” military force against drug trafficking, and to seize foreign leaders and resources. These are examples of serious violations of international humanitarian law (“IHL”)—the law governing the conduct of force. IHL applies only within armed conflict and, to a lesser extent, in zones of military occupation. Outside those situations, the permissive rules of IHL to kill or detain do not apply. Human rights law does. Even within armed conflict zones where IHL does apply, grave violations of protections of civilians and other protections are now common. To ensure the full enjoyment of human rights, the law prohibiting resort to force needs to be honored. Renewing respect for this foundation principle will in turn promote respect for IHL and human rights law.
This article tracks the decline of respect for the prohibition of force, IHL, and human rights law. At the same time, it will clarify the inter-relationship of the three bodies of international law relevant to armed conflict. The article also considers why presidents first began to “abandon peace.” The evidence indicates that a major reason involves the influence of realist political theory. Realism asserts that national security is attained by amassing and demonstrating superior military capability. A president who follows the theory will defy the law against the use of force. Following realism is also at odds with the empirical evidence of what actually produces a more secure world. What works is compliance with the rule of law at home and abroad. National security policy that aligns with international law can succeed and in a way that should even convince realists. Artificial intelligence is a powerful new tool that will help make the case for compliance with the international law of peace.
Recommended Citation
Mary E. O'Connell,
The Prohibition of Force is the First Principle of International Humanitarian Law,
70
St. Louis U. L.J.
(2026).
Available at:
https://scholarship.law.slu.edu/lj/vol70/iss2/4