In recent weeks, Ukraine’s swift counteroffensive has led to the discovery of yet more heinous acts committed by Russian forces against Ukrainian military personnel and civilians. These add to a growing list of atrocities discovered in towns like Bucha and Irpin. Indeed, as the war has ground on, we have heard a lot about Russia committing crimes of aggression and crimes against humanity, possibly even genocide. The types of crimes are numerous and somewhat confusing. It’s worth taking a moment to sort out the differences between the basic categories of crimes, to better understand what’s happening in Ukraine, and to contemplate what these crimes may mean for the future of world peace.

A man with a shirt marked “war crimes prosecutor” with police officers near a residential tower hit by a Russian missile in the Serhiivka village of the Bilhorod-Dnistrovskyi district, Ukraine, July 1, 2022. (Laetitia Vancon/The New York Times)]
A man with a shirt marked “war crimes prosecutor” with police officers near a residential tower hit by a Russian missile in the Serhiivka village of the Bilhorod-Dnistrovskyi district, Ukraine, July 1, 2022. (Laetitia Vancon/The New York Times)

The laws of war fall into two basic types: one set governs whether it is legal for a state to go to war against another, or jus ad bellum. The other set lays out how all actors should conduct themselves in the midst of fighting, or jus in bello.

The Right to Go to War

Jus ad bellum derives from “just war” doctrine dating at least back to the work of St. Thomas Aquinas in the 1200s. The concept of just war re-emerged after Europeans fought each other for multiple decades, culminating in the treaty of Westphalia in 1648. It emerged again after hundreds of millions of people perished in World Wars I and II. Today, using military force against a sovereign state is considered “just” for only three reasons under international law:

  1. In self-defense;
  2. When one state asks another state to send troops (for example, Russia legally sent troops to Syria by invitation of the Assad government); and
  3. If the U.N. Security Council determines that the war is legal under Article 51 of the U.N. Charter (for example, after Saddam Hussein invaded Kuwait, the Security Council authorized a multinational military response).

Russia’s war against Ukraine does not meet any of the criterion for just war. NATO and EU institutional expansions, while possibly undiplomatic, did not constitute acts of war against Russia. In contrast, Ukraine is confronting kinetic military aggression waged by a neighboring state. Ukraine’s resort to self-defense, and invitations for external military assistance are legal under international law. The U.N. Security Council has been stymied because Russia is a permanent, veto-wielding member.

Historically, weakening sovereignty norms have sparked the deadliest periods in world history. The fundamental danger of Putin’s war of aggression against Ukraine is that it opens the door for other states to violate the principles of sovereignty and jus ad bellum. Without these principles, inter-state war threatens every state, and thus every individual, in the world.

Right Conduct During War

Jus in bello, also referred to as international humanitarian law (IHL), applies to all warring parties irrespective of the reasons for the conflict. It does not speak to whether or not the cause of war is just. Instead, this body of law seeks to protect war victims and their fundamental rights, no matter to which party they belong. The four Geneva Conventions constitute the central pillars of IHL:

  1. The first convention, dating back to 1864, stipulates that the sick and wounded should be protected impartially, and that medical facilities should not be targeted during fighting.
  2. The second extends the first convention to the shipwrecked.
  3. The third requires that all warring parties treat prisoners of war humanely, and that prison camps should be open to inspection by neutral countries or entities.
  4. The fourth convention, agreed on the heels of World War II in 1949, requires U.N. member states to punish those who commit crimes such as unlawful killing, torture, serious bodily injury or suffering, unlawful deportation (ethnic cleansing), unlawful confinement, and gender-based crimes such as rape and forced prostitution. The fourth convention includes three additional protocols, extending civilian protections to victims of wars against racist regimes, wars of self-determination and internal conflicts.

Genocide

A separate “Convention on the Prevention and Punishment of the Crime of Genocide” known simply as the genocide convention, lists five acts that can be punishable as genocide. These can be committed in the context of war, or not. Genocide is based on one party’s “intent to destroy, in whole or in part, a national, ethnical, racial or religious group.” Intent is the main bar to determine whether genocide is taking place, and not the overall number of people killed. The acts include causing serious bodily or mental harm to members of the group; deliberately inflicting conditions of life calculated to bring about the group’s physical destruction in whole or in part; imposing measures intended to prevent births within the group; and forcibly transferring children of the group to another group. Article 1 notes that the contracting parties to the convention undertake not just to punish, but to prevent, genocide. 

Russia’s Crimes

In surveying these various crimes, it would seem that Russia today is committing three essential types of crimes: a war of aggression, war crimes and genocide. Early in the war, a majority of member states in the U.N. General Assembly recognized Russia as the aggressor. Additionally, even though U.N. Security Council action is hampered because of Russia’s veto power, at a Security Council meeting on September 27 several states charged Russia with jus ad bellum violations. In terms of Russia’s crimes while conducting the war, the International Criminal Court and the U.N.’s Independent International Commission of Inquiry on Ukraine have documented evidence of acts that appear to constitute war crimes, such as indiscriminate killings and sexual and gender-based violence against civilians. Finally, more than one dozen states have submitted documentation to the International Court of Justice with allegations of genocide being committed by Russia in Ukraine.

Although all of these are horrendous crimes, the crime of aggression in particular threatens the very fabric of the international laws that enable all states to exist without constant threats to their borders. Upholding international law makes peace possible. Russia’s leaders must be held to account.

Dr. Lise Morjé Howard is a senior scholar in residence at the U.S. Institute of Peace. She is also a professor of Government and Foreign Service at Georgetown University (on leave, 2022-23) and the president of the Academic Council on the United Nations System.


Related Publications

Ambassador William Taylor on Ukraine’s Refusal to Cede Territory to Russia

Ambassador William Taylor on Ukraine’s Refusal to Cede Territory to Russia

Thursday, October 3, 2024

Ukrainian President Volodymyr Zelenskyy’s speech at the U.N. General Assembly made clear that Ukraine will not give up claims to territory. “Even if they don’t get [the land] all back right away, they will eventually get it back,” says USIP’s Ambassador William Taylor, which will leave Putin with “no choice but to look for a way out.”

Type: Podcast

Why Is the U.S. Deploying Long-Range Missiles in Germany?

Why Is the U.S. Deploying Long-Range Missiles in Germany?

Wednesday, August 21, 2024

On the sidelines of last month’s NATO summit, the United States and Germany announced that Washington will begin episodic deployments of long-range conventional capabilities to Germany. In 1987, the United States and Soviet Union agreed to eliminate these systems under the Intermediate-Range Nuclear Forces (INF) treaty, but Russia’s violations led the United States to withdraw from the treaty in 2019. Three years later, Russia invaded Ukraine and has engaged in nuclear saber-rattling since then. Washington plans to deploy these systems to strengthen deterrence, but Moscow has criticized them.

Type: Question and Answer

Global Policy

Russia’s War and China’s Rise Set a New Path for South Korea-NATO Relations

Russia’s War and China’s Rise Set a New Path for South Korea-NATO Relations

Tuesday, August 20, 2024

July 2024 marked the third time South Korean President Yoon Suk-yeol joined a NATO summit along with the leaders of the alliance’s other Indo-Pacific partner countries (Australia, Japan and New Zealand), informally known as the IP4. This represents a new phase in South Korea’s relations with the Atlantic alliance, but building a lasting friendship will take time and requires navigating a series of challenges. Amid an emerging global division of democratic and authoritarian camps and the challenges posed by China and Russia for both the Indo-Pacific and Euro-Atlantic regions, it is incumbent on both Brussels and Seoul to build a more cooperative relationship. That journey, however, has just begun.

Type: Analysis

Global Policy

Ukraine’s Pivot Changes the Narrative in Russia’s war; Outcome Remains Unclear

Ukraine’s Pivot Changes the Narrative in Russia’s war; Outcome Remains Unclear

Thursday, August 15, 2024

Almost 30 months into Vladimir Putin’s brutalization of Ukraine with a full-scale invasion that has pulverized vast swaths of its farmlands, towns and cities, Ukrainians have surprised Putin and the world by driving the war back into Russia — a move that, if nothing else, has altered the current narrative around this conflict. Ukraine has again brandished its determination, initiative and innovation, effectively resetting assumptions in its defense against its much larger attacker. The possible outcomes of Ukraine’s strike remain varied and unpredictable — and its eventual implications will rest on the evolutions of several questions, both military and political.

Type: Analysis

Global Policy

View All Publications