War Crimes & the International Criminal Court

01 / Definition

What Is a War Crime?

The modern legal definition comes from Article 8 of the Rome Statute, the treaty that created the ICC. It groups war crimes into four buckets, depending on the type of conflict and the type of act.

1. Grave Breaches of the Geneva Conventions

The most serious violations against people or property protected by the 1949 Geneva Conventions during an international armed conflict — willful killing, torture, inhuman treatment, hostage-taking, unlawful deportation or confinement, and forcing a prisoner of war to serve the enemy.

2. Other Serious Violations in International Conflict

A longer list of prohibited acts in war between states: intentionally attacking civilians, hospitals, schools, or religious and historic sites; using child soldiers; pillaging; using weapons designed to cause unnecessary suffering; and outrages upon personal dignity, including rape and sexual slavery.

3. Violations of Common Article 3

In a civil war or other non-international conflict, this bans violence against anyone not actively fighting — including captured or wounded combatants — covering murder, mutilation, cruel treatment, and taking hostages.

4. Other Serious Violations in Non-International Conflict

A parallel list to category two, applied to internal conflicts: attacking civilians or aid workers, using child soldiers, pillaging, and sexual violence — but it does not cover ordinary internal unrest like riots or isolated acts of violence.

War crimes are one of four crimes the ICC can prosecute. The other three are genocide (acts meant to destroy a national, ethnic, racial, or religious group), crimes against humanity (15 listed acts — including murder, enslavement, torture, rape, and enforced disappearance — committed as part of a widespread or systematic attack on civilians), and, since 2010, the crime of aggression (a state's unlawful use of armed force against another state's sovereignty).

02 / History

The Story of the ICC

The idea of putting individuals — not just states — on trial for atrocities goes back to the Nuremberg and Tokyo tribunals after World War II, which established that following orders was not a defense for mass killing. For decades afterward, the idea of a permanent court stalled in UN committees, frozen by Cold War politics.

The push came back to life in the 1990s, when the UN Security Council created two ad hoc tribunals to respond to specific atrocities: the ICTY for the wars in the former Yugoslavia, and the ICTR for the Rwandan genocide. Over roughly two decades, the ICTY alone tried 161 people and convicted 90, including Bosnian Serb leaders Radovan Karadžić and Ratko Mladić for genocide at Srebrenica; Slobodan Milošević, the first sitting head of state ever indicted by an international court, died before his verdict.

Those tribunals proved international prosecution was possible — but they were temporary and conflict-specific. In June–July 1998, more than 160 governments met in Rome and negotiated the Rome Statute, adopted on July 17, 1998, by a vote of 120 in favor to 7 against (including the United States, Israel, and China) with 21 abstentions. After the 60th country ratified it, the treaty entered into force on July 1, 2002, formally creating the ICC as the first permanent international criminal court — seated in The Hague, Netherlands, and intended to step in only when national courts are unwilling or unable to prosecute.

03 / Convictions

Who the ICC Has Actually Convicted

The ICC has secured a small number of convictions since 2002 — prosecuting individuals is slow, and the court has no police force of its own to make arrests.

*Karadžić and Mladić were tried by the ICTY, the ad hoc UN tribunal that preceded the ICC, not the ICC itself.

04 / Current Cases

Wanted & In Custody Now

ICC member states are legally obligated to arrest anyone under an ICC warrant who sets foot on their territory, though enforcement varies widely in practice.