War Crimes, Genocide, and Crimes Against Humanity, Explained 

Almost immediately after Hamas’ October 7 incursion into Israel, in which its terrorists killed more than 1,400 people and took more than 200 hostages—including children and elderly—it faces accusations of war crimes, genocide, and crimes against humanity. 

U.S. Rep. Michael McCaul, for example, said in an October 19 letter to Secretary of State Antony Blinken that Hamas’ actions went beyond terrorism, but included “the full range of atrocity crimes under international law.”

Accusations of any of these crimes carry hefty legal and moral implications—beyond geopolitical polemics—and unfounded accusations damage the causes of real victims of atrocity. 

How are war crimes defined?

War crimes are breaches of international law perpetrated within an armed conflict, with the armed conflict component—whether international or not—differentiating them from genocide or crimes against humanity. War crimes may be breaches of treaties, such as the 1998 Rome Statute of the International Criminal Court, or the theory of jus cogens, peremptory norms and customs that all actors are expected to adhere to, even without a treaty.

The Nuremberg trials of former Nazi leaders in 1945 and 1946 weren’t the first “war crimes” trials, but they did represent the largest single trial of war criminals at one time. In the initial tribunal, 24 military and political leaders were tried—three of whom posthumously—with 19 defendants convicted and 12 sentenced to death. Dozens more members of the Nazi apparatus were tried in later years. These trials codified war crimes and crimes against humanity in international law and offered case law for later trials. 

War crimes were most recently defined in Article 8 of the 1998 Rome Statute of the International Criminal Court, which prohibited murder (typically understood as killing non-combattants); rape; torture; taking of hostages; and intentionally targeting civilians and/or civilian infrastructure. The statute also added protections for wounded members of enemy armed forces, prisoners of war, civilians, humanitarian workers, and medical and religious personnel. 

Notably, neither Israel nor the United States is party to the International Criminal Court (ICC). Both states signed the Rome Statute, but did not ratify it. In 2015, the Palestinian Authority (PA) signed on to the Rome Statute and became a party to the ICC, which gave the court jurisdiction over crimes perpetrated by the PA or within its territory. The ICC maintains it has the authority to exert jurisdiction when a citizen of a non-member country commits war crimes, crimes against humanity, or genocide in the territory of an ICC member country. 

But both Hamas and Israel are bound by the laws of armed conflict and jus cogens, as David French covered extensively in the New York Times recently.

How is genocide defined?

Genocide and crimes against humanity are distinct crimes within international human rights law, though they are often used interchangeably and alongside accusations of war crimes. All genocides are crimes against humanity, but not all crimes against humanity constitute genocide—they differ in two key ways. First, genocide is a discriminatory crime, perpetrated against an individual because of membership in a particular group. Genocide also involves intent to destroy the targeted group, in whole or in part.

The word genocide was coined by Polish-Jewish lawyer Raphael Lemkin in his 1943 book Axis Rule in Occupied Europe. He defined it as “ a coordinated plan of different actions aiming at the destruction of essential foundations of the life of national groups, with the aim of annihilating the groups themselves.” 

The crime of genocide was first codified in Article 2 of the United Nations’ 1948 Convention on the Prevention and Punishment of the Crimes of Genocide, and later included in Article 6 of the 1998 Rome Statute of the ICC. Within this legal framework, genocide is defined as: “Acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group.” This includes “killing members of the group; causing serious bodily or mental harm to members of the group; deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part; imposing measures intended to prevent births within the group; forcibly transferring children of the group to another group.” 

Victims of genocide are targeted for their membership in national, ethnical, racial, or religious groups—political groups are not included. Genocide also requires proof of intent. Genocide was first included in a criminal conviction in 1998 during the International Criminal Tribunal for Rwanda (ICTR) in response to the 1994 Rwandan genocide. Jean Kambanda, the former prime minister of Rwanda, pleaded guilty to the charge of genocide. The International Criminal Tribunal for the Former Yugoslavia included former President Slobodan Milosevic, the first head of state to be tried with war crimes, crimes against humanity, and genocide. He died in 2006 before his trial concluded, however. The tribunals are the blueprints for the International Criminal Court, and offer a path to successfully prosecuting individuals for genocide. 

Under the 1948 convention, signatories are obligated to prevent and punish instances of genocide, whether occuring in peace or wartime, by governments, groups, or individuals. This obligation does raise the stakes for world leaders to call an atrocity a genocide—acknowledging a genocide may obligate a response, even if ill-defined in documents defining genocide. President Bill Clinton faced criticism in 1994 for his administration’s refusal to call the atrocities in Rwanda genocide because it could have obligated the United States to intervene despite there being no defined international process for doing so.

How are crimes against humanity defined?

Crimes against humanity is a unique category from genocide and war crimes, encompassing crimes committed against civilians outside active conflicts. All genocides are crimes against humanity, but not all crimes against humanity constitute genocide. 

Crimes against humanity are defined in Article 7 of the Rome Statute of the ICC as acts “committed as part of a widespread or systematic attacked directed against any civilian population, with knowledge of the attack,” including murder; extermination; enslavement; deportation; imprisonment against international law; torture; rape; forced pregnancy or sterilization; persecution; forced disappearances; apartheid. 

Crimes against humanity are more easily defined than genocide because doing so does not require an intent to exterminate a particular group. But it does require proof of willfully targeting civilians in a systematic attack.

Israel is most often accused of the crime of apartheid for its system of checkpoints and roadblocks in Gaza and the West Bank. Apartheid in international law is defined in the 1998 Rome Statute as “inhumane acts … committed in the contexts of an institutionalized regime of systematic oppression and domination by one racial group over any other racial group or groups and committed with the intention of maintaining that regime.”

Israel maintains these policies are a response to ongoing terror activities, not a discriminatory system. The Palestinian Authority is also accused of apartheid for its insistence that territory it controls be free of Jews, even sentencing Palestinians who sell land to Jews to life in prison. 

The ICC requires member cooperation in order to charge and convict individuals of atrocity crimes. Earlier this year, the ICC issued arrest warrants for Russian President Vladimir Putin and Maria Alekseyevna Lvova-Belova, the Russian commissioner for children’s rights. Both are charged with war crimes and crimes against humanity for deporting children from Ukraine and transferring them from occupied areas of Ukraine to the Russian Federation. 

What do these terms mean in relation to the Israel-Hamas war?

Understanding that these terms have specific legal definitions affects how we understand the conflict, how we draw comparisons to other tragedies, and what we expect from any future peace negotiation. As international bodies seek peace—whether through a ceasefire, a disarmament, or by force—accurate understanding of the atrocities committed affects the way international viewers understand the conflict. 

Footage released by Israel of Hamas terrorists’ body cameras prove Hamas intentionally targeted civilians for slaughter. Israel’s critics—which include foreign leaders and international organizations—have also accused Israel of committing war crimes, crimes against humanity, and genocide through their response to Hamas’ attack. But those allegations often ignore the actions of Hamas in the region and its stated cause of creating a Palestinian state from the Jordan River to the Mediterranean Sea—a complete erasure of Israel. 

Even with obvious breaches of international law, the ICC does not have its own police force—it can not execute warrants. Instead, the ICC relies on member states for enforcement power. It is unlikely, for instance, that Putin will ever face charges in front of the ICC unless a new Russian regime decides to extradite. It remains to be seen what the international community is willing to do to hold criminals in the Israeli-Hamas conflict accountable.

Click here for more coverage of the war in Israel.