Prosecuting War Criminals Would Be A Lot Easier If Not For The United States' Resistance

We may earn a commission from links on this page.
Image for article titled Prosecuting War Criminals Would Be A Lot Easier If Not For The United States' Resistance
Photo: Elena Scotti (GMG)

This piece is part of a recurring series that aims to be a complete guide to the laws of war. You can read previous entries here.

International criminal law is the body of laws that seeks to bring justice to those responsible for the worst crimes committed in situations of armed conflict and serious violence.


Until relatively recently in history, there existed no international legal framework for punishing the perpetrators of the most serious crimes of international concern. Historically, war crimes were dealt with under the notion of collective responsibility, in which a nation would make reparations to another for the wrongs of its state officials. Despotic rulers who committed atrocities against their own population would never be brought to justice before their own national courts until they had fallen from power, and in the international arena they were protected absolutely by the unbreachable bulwark of sovereignty, which mandated non-interference by the international community in so-called “internal” affairs.

The doctrine of international criminal responsibility emerged with the development of international law on piracy and, toward the end of the 19th century, war crimes. The historic convictions at Nuremberg marked the dawn of international criminal law and the foundation of the modern international justice movement. After decades of stagnation, international criminal law has engineered significant momentum in the new millenium, with its substantive law, its judicial and administrative infrastructure, and the international community’s enthusiasm for its enforcement all developing rapidly since the mid-1990s.


Let’s take a tour through international criminal law and examine the content of its three main crimes.

International Criminal Tribunals Through The Years

At the conclusion of World War II, the victorious Allies wrestled with the question of how to seek justice for the crimes committed by the Nazis in Europe and by Japanese personnel during its occupation of large parts of South-East Asia.

Although Winston Churchill wanted to simply hang or imprison Nazi leaders with a minimum of fuss and without having to hold pesky fair trials, Roosevelt and Stalin insisted on the creation of specialized judicial bodies to prosecute atrocities committed during the war. Therefore the Allies created the first-ever international criminal tribunals created to punish violations of the laws of armed conflict: the International Military Tribunal at Nuremberg (the Nuremberg Tribunal, established under the treaty known as the Nuremberg Charter) and the International Military Tribunal for the Far East (the Tokyo Tribunal, established by executive order of General Douglas MacArthur, Supreme Commander of the Allied Powers in Japan).

The Nuremberg and Tokyo Tribunals were granted jurisdiction over three classes of crime: war crimes, crimes against humanity, and crimes against peace (which largely corresponds to what we today refer to as the crime of aggression). Nineteen Nazis were convicted in the initial Nuremberg trial of major war criminals, while 25 Japanese personnel were convicted at the headline Tokyo trial. Some six thousand Nazis were convicted in subsequent years in West German courts, while around 4,800 were convicted in the Far East.


The Nuremberg trials heroically confirmed the doctrine of individual criminal responsibility: that a person is individually liable for serious violations of international law that they commit, and that other persons may be liable for assisting, planning, instigating, or failing to prevent such crimes. Famously, the Nuremberg Charter provided an accused could not be absolved of responsibility simply because they were following orders. Nuremberg’s legacy lives on as the foundation of international criminal justice.

The Tribunals’ success and the international community’s zeal to forge a new post-War era led to three historic legal landmarks: 1948 Universal Declaration of Human Rights, the 1948 Genocide Convention, the four 1949 Geneva Conventions. It did not, however, lead to the creation of a permanent international criminal court which would be equipped to dispense Nuremberg-type justice as needed. The idea was initially pursued: in the same resolution which adopted the Genocide Convention, the United Nations General Assembly invited the International Law Commission “to study the desirability and possibility of establishing an international judicial organ for the trial of persons charged with genocide.” The ILC produced draft statutes for the foundation of such a court in 1951 and 1953, but they were not adopted as the possibility of superpower consensus quickly vanished amidst Cold War posturing. We can only speculate what effect fifty extra years of prosecutions, jurisprudence, reparations, and precedential deterrence would have had on international peace and security.


It was not until the 1990s that a confluence of factors created an atmosphere where the international community was ready to dip its collective toe back into the sphere of transnational criminal justice. The Cold War was over, and a new era of consensus-building amongst the world’s strongest nations seemed to be achievable, demonstrated by the coordinated condemnation and action toward Saddam Hussein’s invasion of Kuwait in 1990. Any consensus, however, coalesced more easily around reaction rather than positive action, and when the United Nations Security Council shamefully failed to intervene to prevent atrocities committed in Rwanda and the former Yugoslavia only a few years thereafter, it belatedly moved to make up for its embarrassment by creating two specialized judicial bodies in 1993 and 1994.

The International Criminal Tribunal for the former Yugoslavia (the ICTY) was created by a Security Council resolution and empowered to prosecute grave breaches of the Geneva Conventions, violations of the laws and customs of war, genocide, and crimes against humanity committed in the former Yugoslavia since January 1, 1991. The International Criminal Tribunal for Rwanda (the ICTR) was likewise established by the Security Council and was empowered to prosecute genocide, crimes against humanity, and violations of Article 3 common to the four 1949 Geneva Conventions perpetrated in Rwanda or neighboring territory during 1994.


The first decision handed down by the Appeals Chamber of the ICTY, the famous Tadić decision of October 2, 1995, was perhaps the most important international law decision of the 20th century. The identity of the defendant was beside the point—Duško Tadić was merely a small-time freelancing thug—but as the first judgement of an international criminal tribunal since World War II, the decision had an immeasurable effect on the development of international criminal and humanitarian law. From a legal point of view, Tadić gave the international community definitions of international and non-international armed conflicts and defined their geographic and temporal scopes, confirmed for the first time that war crimes could be punished when committed in non-international armed conflict, and confirmed that purely internal conflicts and violations of humanitarian law could constitute threats to international peace and security, as well as providing important findings in relation to myriad other important legalistic issues.

Over their lifetimes, the ICTY and ICTR convicted hundreds of criminals, brought some measure of justice to victims and their families, and strengthened international criminal and humanitarian law by providing invaluable jurisprudence to the legal notions of genocide, crimes against humanity, and war crimes, including landmark judgements in relation to rape and sexual violence in conflict.


The two tribunals shared an Appeals Chamber, which sat in the Hague in the Netherlands along with the ICTY’s Trial Chamber. The Trial Chamber of the ICTR was located in Arusha, Tanzania, the site of the 1993 peace agreement which had been intended to bring an end to the Rwandan Civil War. Having fulfilled their mandates, the ICTR and ICTY ceased operations on December 31, 2015 and December 31, 2017 respectively.

In the years since, several other ad hoc criminal tribunals have been established, each being so-called “hybrid” or “internationalized” bodies featuring a mix of international and local judges and staff, in contrast to the purely international ICTY and ICTR.


The Special Court for Sierra Leone was established under agreement between the government of Sierra Leone and the United Nations to prosecute crimes against humanity, violations of Article 3 common to the four Geneva Conventions, and other serious violations of IHL committed during Sierra Leone’s 1991-2002 civil war. The innovative justice agreement placed an emphasis on healing and reconciliation, with the Court sitting in Freetown where it could deliver justice at the scene of past crimes and be most accessible to the affected population, and with the venerable Truth and Reconciliation Commission mandated to construct an impartial historical record of human rights violations, addressing impunity, investigating the causes of the conflict, and to provide an opportunity for healing and reconciliation between victims and abusers. The Court’s most notable achievement was the prosecution of former Liberian president Charles Taylor, who was sentenced to 50 years imprisonment for planning and aiding and abetting war crimes and crimes against humanity, the first conviction of a former head of state for war crimes since Nazi admiral Karl Dönitz at Nuremberg.

The Special Panels for Serious Crimes, or the East Timor Tribunal, was established by the United Nations Transitional Authority in East Timor, which so acted between the end of Indonesian occupation in 1999 and the independence of East Timor in 2002. The Transitional Authority’s regulation gave jurisdiction to the existing Dili District Court over genocide, war crimes, crimes against humanity, murder, and sexual offenses committed between January 1 and October 25, 1999.


The Extraordinary Chambers in the Courts of Cambodia was established by agreement between the United Nations and the Cambodian parliament in 2001 to prosecute crimes committed by “senior leaders of Democratic Kampuchea” (the Khmer Rouge) during its reign from 1975-1979. The push for a hybrid court featuring a majority of international judges was rejected by Cambodian dictator Hun Sen, who just so happened to have been one of Pol Pot’s principal lieutenants prior to his defection to Vietnam in 1977. Instead, the court as ultimately agreed features a majority of Cambodian judges, with the Cambodian government having final say over the appointment of international judges, the prosecutor, and the registrar. Still in operation today, the ECCC has jurisdiction over genocide, crimes against humanity, grave breaches of the Geneva Conventions, destruction of cultural property, and the Cambodian penal law crimes of homicide, torture, and religious persecution. Although the Court has moved at a glacial pace and suffered from significant political interference (most vividly in the investigation, arrest, and indictment process), it has secured the convictions of the two most senior living Khmer Rouge leaders Nuon Chea and Khieu Samphan, and its outreach program has served to educate the Cambodian public of the atrocities of the past.

The Extraordinary African Chambers were established in order to prosecute former Chad dictator Hissène Habré, estimated to have killed 40,000 of his subjects and tortured 200,000 more. After he was deposed in 1990, the Senegalese government sheltered Habré in exile for nearly 25 years. The tireless efforts of victims groups, NGOs, and the government of Belgium (which had long lobbied for his extradition in order to try Habré under universal jurisdiction) were ultimately successful in shaming Senegal into passing a law for the creation of a specialized international tribunal to try Habré for his crimes. Established within Senegal’s existing court structure and with judges appointed by the African Union, the Chambers were tasked with prosecuting the “person or persons” most responsible for genocide, crimes against humanity, war crimes, and torture committed in the territory of Chad during the period from June 7, 1982 to December 1, 1990, being the exact dates of Habré’s reign. Habré was sentenced to life in prison in 2016, marking the first instance in which the courts of one country prosecuted the former ruler of another for alleged human rights violations, and the first case based on the principle of universal jurisdiction to proceed to trial in Africa. In 2017, an appeals court upheld the guilty verdict and ordered Habré to pay 82 billion Central African francs (approximately US$154 million) in compensation.


The establishment of these judicial bodies, and the arrest of former Chilean dictator General Pinochet in London in 1998 based on an international warrant issued by a Spanish magistrate, were major milestones in the long fight toward overcoming impunity in international crimes.

The International Criminal Court

Ultimately, the successful push for a permanent international criminal court originated from a somewhat unlikely source: in 1989, Trinidad and Tobago asked the UN General Assembly to task the International Law Commission with resuming work on an international criminal court, specifically with jurisdiction to prosecute drug trafficking. It did so, and momentum grew through the 1990s to the point that the international community was ready to make a run at the historic establishment of a new court.


The ILC produced a well-received draft statute, enthusiasm continued to grow, and the nations of the world (and representatives from some 175 NGOs) ultimately descended on Rome in June and July 1998 for the conference at which the final treaty would be thrashed out. Ahead of the conference, three major groupings of states had emerged: the bloc of so-called “like-minded states” led by Canada, Germany, and Australia, which favored a strong court with a universal jurisdiction and a sweeping definition of war crimes; the United States, China, and Russia each wanted the Court to be subservient to the United Nations Security Council and to exclude the use of nuclear weapons from the list of war crimes; and others such as Iraq, Iran, Libya, and Indonesia did not want a court at all.

To its eternal discredit, the United States pushed to weaken the Court as much as possible, particularly fighting to preclude the Court from being granted universal jurisdiction over war crimes and crimes against humanity (threatening allies Germany and South Korea with a troop-pullout if they continued to endorse the proposal). Having done its level best, the United States, of course, withdrew its support for the Court at the conclusion of the conference, and has never become a state party.


Despite these efforts, the document ultimately adopted as the Rome Statute must be considered a signal triumph in the fight for justice, and a headline achievement in modern human history. It granted the new International Criminal Court jurisdiction over persons for the four most serious crimes of international concern: genocide, crimes against humanity, war crimes, and the crime of aggression.

For a case to come before the Court, it must have jurisdiction over the alleged crime, that jurisdiction must be triggered, and the case must be admissible.


The ICC’s jurisdiction may be triggered in three ways. First, a state party to the Court may refer a situation to the Court, as has happened with self-referrals of situations by Palestine, Gabon, Mali, Comoros, Uganda, the Central African Republic (twice) and the Democratic Republic of the Congo. A non-state party can accept the jurisdiction of the ICC on an ad hoc basis by making a declaration to that effect, such as Ukraine has done. A referring state does not need to have any direct connection to the situation in question, and the first-ever (and so far only) referral of a situation occurring on the territory of another state came in 2018 when a group of six American nations referred the situation in Venezuela to the Court. Secondly, the United Nations Security Council may refer a situation to the Court, as has happened twice, with respect to situations in Libya and Darfur, Sudan. Thirdly, the Office of the Prosecutor may of its own motion initiate a preliminary examination on the basis of information on crimes within the jurisdiction of the court (as it has done with situations in the Philippines, Nigeria, Iraq, Guinea, Colombia, and Afghanistan), and on the basis of this examination the Court’s Pre-Trial Chamber may approve a full-blown investigation (as it has done with situations in Burundi, Georgia, Côte d’Ivoire, and Kenya).

Only crimes committed on or after July 1, 2002, the date of entry into force of the Rome Statute, can be brought before the Court. For nations that were not original members, jurisdiction commences on the date they join, unless they choose to make a declaration to accept the Court’s jurisdiction retroactively, as Côte d’Ivoire has done. Crimes are expressly not subject to any statute of limitations. The Court only has jurisdiction over natural persons (not corporations, political entities, and so on), and only those who were at least 18 years of age at the time of the alleged offense. Except in the case of a United Nations Security Council referral, the alleged crime must have been committed on the territory of, or by a national of, a country that is party to the statute. This is the Court’s biggest shortcoming (and was the United States’s biggest victory in Rome): current world leaders will never appear before the Court unless they put all of the Security Council’s permanent members offside, and criminals who enjoy governmental support where they live (as is sadly common in many post-conflict nations) will likewise remain out of reach.


A fundamental feature of the Court is that it is complementary to national criminal jurisdictions, meaning that a case is inadmissible if it is being investigated or prosecuted by a state which has jurisdiction over it, unless the state is unwilling or unable genuinely to carry out the investigation or prosecution. (This stands in contrast to the ICTY and ICTR, which had primacy over national courts.) A conflict may arise here in two ways: where a home nation is dragging its feet in a supposed prosecution in order to shield the accused from justice; or, conversely, where the home nation is all too willing to prosecute them through a sham trial devoid of fair trial guarantees (and is therefore not “genuinely” carrying out the prosecution). The latter issue arose with ICC indictee Abdullah Al-Senussi, former intelligence chief of Muammar Gaddafi, who has been sentenced to death by a Libyan court and who (temporarily benefiting from a stay due to appeal) wishes instead to benefit from the fair trial guarantees in the ICC. Similarly, the rule against double jeopardy means that a person cannot be tried by the Court if they have previously genuinely been tried or investigated and cleared in relation to their crimes. Finally, the Court’s mandate is to focus on the most serious crimes of international concern, and a case will be inadmissible if it is not of sufficient gravity to justify further action by the Court, as was deemed to be the case regarding a referral by the nation of Comoros.

Crucially, the Rome Statute criminalizes command responsibility, whereby a military commander is individually criminally responsible for crimes committed by forces under his or her effective command and control as a result of failure to exercise control properly over those forces. A person’s official capacity is irrelevant to their guilt, and diplomatic or sovereign immunities do not bar the ICC from exercising its jurisdiction. For those of a lower rank, a defense of superior orders may only be invoked in narrow circumstances and only with respect to war crimes.


As would be expected, the Rome Statute grants accused persons comprehensive fair trial guarantees, including the presumption of innocence, protection of the principle of legality, a bar on double jeopardy, non-retroactive application of the law, and rights to a defense, cross-examination, an interpreter, written reasons for a decision, and an appeal. The Court cannot impose the death penalty.

One of the most innovative aspects of the Rome Statute is the establishment of the Trust Fund for Victims, which implements reparations for victims and provides physical and psychological rehabilitation and material support to victim survivors, their families, and affected communities.


Sitting in the Hague in the Netherlands, 123 nations are currently party to the International Criminal Court, with important holdouts including the United States, Russia, China, India, Syria, Iraq, Yemen, and Israel. The current ICC Prosecutor Fatou Bensouda has served in that role since 2012. Thomas Lubanga Dylio became the first person convicted by the International Criminal Court in 2006, being sentenced to 15 years’ imprisonment for enlisting and conscripting child soldiers in Second Congo War.

International Crimes

Let’s now discuss crimes of genocide, war crimes, and crimes against humanity—crimes which are all commonly-referenced but usually incorrectly so. For a discussion of the fourth Rome Statute crime, the crime of aggression (serious violations of the prohibition on the use of force), be sure to visit the second entry in this series.



Although the essence of “the crime of crimes” is by no means a modern phenomenon, prior to World War II genocide had not been articulated as a crime in the manner we speak of today, and past genocidal atrocities were instead described “only” as instances of mass murder. Polish lawyer Raphael Lemkin coined the term “genocide” in his 1944 book Axis Rule in Occupied Europe, combining genos (meaning people or race), with -cide (to kill). It was largely Lemkin’s heroic efforts which led to the term penetrating the public consciousness and to the historic adoption of the Genocide Convention in 1948.


At Nuremberg, Nazi personnel were ether charged with crimes against humanity or war crimes, as the standalone concept of genocide did not yet exist. Since then, domestic courts that have succeeded in tracking down and prosecuting Nazis such as Klaus Barbie (protected for years by the government of Bolivia after being smuggled out of Germany by the Americans) and Adolf Eichmann (infamously snatched from Argentina by Israeli forces under cover of darkness) have often convicted them for war crimes and/or crimes against humanity, which (as we’ll see) are easier to prove. We can’t add Romanian dictator Nicolae Ceaușescu and his wife Elena to the list of genuinely convicted génocidaires—they were tried, convicted, and executed all in one day on Christmas in 1989 in a sham trial in which their appointed defense lawyer declared them guilty of genocide.

It was not until 1998 that Jean Paul Akayesu became the first person ever to be convicted of genocide in an international criminal tribunal: sentenced by the ICTR to life imprisonment for his role in mass killings and rapes of ethnic Tutsis in Rwanda. The only person so far charged with genocide in the International Criminal Court is Sudan president Omar al-Bashir, who is subject to a current arrest warrant for three counts of genocide allegedly committed against the Fur, Masalit, and Zaghawa ethnic groups in Darfur from 2003 to 2008.


The definition in the Genocide Convention, which has been adopted verbatim in every subsequent international instrument criminalizing genocide, reads:

Genocide means any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such:

(a) Killing members of the group;

(b) Causing serious bodily or mental harm to members of the group;

(c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;

(d) Imposing measures intended to prevent births within the group;

(e) Forcibly transferring children of the group to another group.

Genocide may be carried out in time of peace or in time of war. In addition to acts of genocide themselves, conspiracy, incitement, attempt, and complicity are all criminalized.


From the definition, we can see that three conditions must be satisfied to establish genocide. First, that certain criminal acts are carried out; secondly, that the acts are carried out against members of a certain group; and thirdly, that the perpetrator has the special intent to destroy the group as such—the latter being the essence of genocide as distinguished from other crimes.

In the five enumerated acts in paragraphs (a)-(e) above, it can be seen that murder or extermination are not the only methods of genocide. The element of “causing serious bodily or mental harm” has been interpreted as including the rape and sexual violence carried out on Tutsi women and girls by Hutu extremists in Rwanda. Subjecting a group to so-called slow death measures, such as a lack of proper housing, clothing, hygiene and medical care, or excessive work or physical exertion, can satisfy paragraph (c). The forcible transfer of children differs in some respects to the other acts, being aimed not at the biological or physical destruction of the group but to the disappearance of the group through the severance of links with its youngest generation.


The fact that the Convention lists these five acts and these four groups in an exclusive manner is its biggest shortcoming. On this basis, at the international level, extermination of social, cultural, or political groups (such as peasants, suspected communists, or LGBTQ+ persons) could not be classified as genocide. Acts of so-called “cultural genocide,” where the language or customs of a group are specifically targeted, likewise do not fall within the ambit of the Convention. It is possible for states to widen the concept of genocide in their domestic legislation: for example, Ethiopia’s Penal Code includes acts against political groups, while the criminal legislation of Peru, Paraguay, and Lithuania include acts against social groups.

The element which separates genocide from “normal” crimes is the special intent of the perpetrator to destroy the group as such in whole or in part. One person may kill another person of a different race explicitly out of racial hatred, but without an intention to destroy that racial group in whole or in part, the killing would not be classified as genocide. This genocidal intent must be inferred from the circumstances of each case. Evidence may come in the form of the existence of a formal official policy, statements made by the perpetrator and others, and the number of deliberate and systematic atrocities committed against the targeted group. The perpetrator does not need to intend to destroy the whole group nor succeed in doing so—an intention to destroy a substantial part of the group is most likely sufficient.


War Crimes

War crimes are, simply, serious violations of international humanitarian law, the laws discussed in this series. Only the most serious contraventions amount to war crimes: a soldier who steals a loaf of bread in an occupied village or a commander who runs a prisoner of war camp without possessing a copy of the Third Geneva Convention have both breached the laws of war, but neither act is serious enough to give rise to individual criminal responsibility that could see them hauled before the International Criminal Court.


All nations of the world have the right to vest universal jurisdiction in their national courts over war crimes, meaning that there does not need to be any link between the war crime and the prosecuting country for such a case to be brought. This right exists in addition to the obligation to provide for universal jurisdiction over war crimes classified as grave breaches, and, more broadly, countries’ inherent right to vest criminal jurisdiction in its courts when the crime occurs on its territory or is committed by or against one of its nationals.

States are required to investigate war crimes allegedly committed by their nationals or armed forces, or on their territory, and, if appropriate, prosecute the suspects. Statutes of limitation may not apply to war crimes.


In the International Criminal Court, the defined list of applicable war crimes is thematically broken up into four discrete categories: acts criminalized as grave breaches in the Geneva Conventions and the first Additional Protocol in international armed conflict; violations of Article 3 common to the Conventions in non-international armed conflict; and other serious violations of the laws of international and non-international armed conflict. The validation of the Tadić finding that war crimes can be committed in non-international armed conflict confirms forever that there can be no immunity for atrocities visited by a ruling power on its own population.

Across these four categories, 53 discrete war crimes are listed in the Rome Statute (with some overlap where identical acts are war crimes equally in international and non-international armed conflict), which may be thematically categorized along the following lines:

  • Attacks committed against persons not or no longer taking part in hostilities, including murder, torture, or sexual violence, against civilians, prisoners of war, combatants hors de combat, and other protected classes.
  • The use of prohibited means of warfare, such as expanding bullets, asphyxiating gases, and poison.
  • The use of prohibited methods of warfare, including attacks directed at the civilian population, disproportionate attacks, acts of terrorism, starvation as a method of warfare, declaring that no quarter shall be given, and the use of human shields.
  • Criminal acts against specially protected persons and objects, such as medical personnel and units, United Nations peacekeepers, and members and objects of the International Committee of the Red Cross.
  • The improper use of protected signs and emblems, such as a flag of truce or surrender, the protective emblems of Geneva Conventions, the uniform of the enemy, or of the United Nations.
  • Conscripting or enlisting children under the age of fifteen, or using them to participate in hostilities.

Crimes Against Humanity

The notion of crimes against humanity recognizes that some atrocities—namely widespread or systematic attacks on a civilian population—shock the conscience to such a degree that their commission demeans us all as human beings. There ought to be a universal jurisdiction to try these crimes because they cannot be thought to be only a matter of concern to the nation in which they were committed, and so the walls of sovereignty must be breached if that is necessary to bring about justice.


The phrase “crimes against humanity” was first used in a 1915 joint statement by the British, French, and Russian governments in decrying mass killings of Armenians in the Ottoman Empire. The Russian foreign minister had originally proposed decrying Turkey’s “crimes against Christianity,” but the French foreign minister lamented that France and Britain’s Muslim populations would complain of being excluded by such a formulation and instead proposed the wording “crimes against humanity and civilization.”

Many acts of the Nazis during World War II were not criminalized by customary international law as it then existed, as the laws of war then did not address inhumane acts against a nation’s own citizens (or those of its allies). The Nuremberg Charter hedged on making crimes against humanity a completely new discrete category of crime—it criminalized certain acts against a civilian population as crimes against humanity, but required that they have been committed in connection with other crimes under the Tribunal’s jurisdiction (crimes against peace and war crimes).


A crime against humanity is made up of three legal elements: that certain criminal acts are carried out, as part of and with knowledge of a widespread or systematic attack, with the attack being directed against a civilian population.

The individual acts which can constitute crimes against humanity are notionally divided into two groups: so-called murder-type offenses which are mostly already criminalized by domestic criminal laws, and so-called persecution-type offenses which cover acts which may in normal circumstances be lawful. In the International Criminal Court, murder-type offenses include extermination, enslavement, deportation or forcible transfer of a population, arbitrary imprisonment, torture, rape, sexual slavery, forced pregnancy, enforced sterilization, enforced disappearance, and the crime of apartheid. Persecution is classified as depriving persons of fundamental rights contrary to international law by reason of the identity of a group or collectivity.


In the International Criminal Court, a widespread or systematic attack on the civilian population must be pursuant to or in furtherance of a state or organizational policy to commit such attack, in that the state or organization actively promotes or encourages the attack. The perpetrator of a crime against humanity does not need to have knowledge of all characteristics of the attack or the precise details of the plan or policy, but must simply know that there is an attack and that their actions comprise part of it.

Finally, the attack must be “directed against any civilian population”. Some individual victims may be non-civilians (i.e., military combatants), so long as the attack at large is direct at a civilian population.


Arguably, the limitation of the crime only to attacks against a civilian population is unjust: crimes against humanity may be committed in times of peace, rendering the distinction between civilians and combatants functionally irrelevant, and there seems to be no principled reason for not criminalizing an attack on, say, ethnic minority members of a nation’s military by its own government.

Since Nuremberg, crimes against humanity have been offenses at customary international law, but there has never been a standalone treaty for the crime, although the conventions on genocide, apartheid, torture, and enforced disappearance all recognize certain offenses as crimes against humanity. In recent years, work by groups such as the Crimes Against Humanity Initiative have created momentum for the adoption of a dedicated treaty, with the International Law Commission currently undertaking significant work to propose draft articles for such a treaty, incorporating the Rome Statute definition of the crime verbatim.


The absence of a specialized crimes against humanity treaty is an unjustifiable gap in the framework of international criminal justice, and its future creation, should it come to pass, will be a belated step in the right direction.

That concludes our series on the laws of war, good people. We’ve covered a lot of ground: the general principles of international humanitarian law; the prohibition on use of force; the principle of distinction; protections owed to the wounded and sick, prisoners of war, and civilians; the law of occupation, the conduct of hostilities, the means and methods of warfare, and international criminal law. Thanks for reading.