War Crimes: A Primer

"The Russian invasion of Ukraine has given rise to numerous accusations of war crimes. This Legal Sidebar addresses the sources and content of the law of war, also known as the law of armed conflict or international humanitarian law (IHL) as it pertains to war crimes that occur in an international armed conflict. IHL applies to the conduct of war; it does not address the legality of the war itself. For information about potential accountability for war crimes in international tribunals, see CRS Legal Sidebar LSB10704, The Role of International Tribunals in the Response to the Invasion of Ukraine, by Nina M. Hart and Stephen P. Mulligan.

Sources of International Humanitarian Law

IHL is a combination of international treaties and customary international law. The Hague Convention of1907 generally prescribes rules of conduct for armed forces, while the Geneva Conventions and Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts 1 (Protocol 1) address the rights of protected persons, such as civilians and prisoners of war, in an international armed conflict. Not all states are parties to these and other treaties pertaining to the law of war, but many provisions are regarded as reflecting customary international law, which is binding on all states.

Principles of International Humanitarian Law.

Certain principles undergird IHL and form the basis for the content of war crimes and serve to reduce unnecessary suffering during war. The most important principles are military necessity, humanity, and honor. The principles of distinction and proportionality flow from the first three. The Department of Defense’s Law of War Manual describes their interaction as follows:

Military necessity justifies certain actions necessary to defeat the enemy as quickly and efficiently as possible. Conversely, humanity forbids actions unnecessary to achieve that object. Proportionality requires that even when actions may be justified by military necessity, such actions not be unreasonable or excessive. Distinction underpins the parties’ responsibility to comport their behavior with military necessity, humanity, and proportionality by requiring parties to a conflict to apply certain legal categories, principally the distinction between the armed forces and the civilian population. Lastly, honor supports the entire system and gives parties confidence in it. (Citations omitted).

The main purposes of the law of armed conflict are:

 Protecting combatants, noncombatants, and civilians from unnecessary suffering;
 Providing certain fundamental protections for persons who fall into the hands of the enemy, particularly prisoners of war, military wounded and sick, and civilians;
 Facilitating the restoration of peace;
 Assisting the commander in ensuring the disciplined, ethical, and effective use of military force;
 Preserving the professionalism and humanity of combatants; and
 Preventing the degeneration of warfare into savagery or brutality.."
War crimes