The Convention on the Prevention and Punishment of the Crime of Genocide is considered the principal guiding legal standard in any analysis of whether a situation constitutes genocide. The legal definition of genocide is contained in Article 2.

Elements of the definition
The definition comprises two basic elements of the offense called genocide: a physical or material one and a mental or moral one. The material element is the physical destruction of national, ethnic, racial and religious groups. The convention gives an exhaustive list of acts constituting the crime of genocide, which does not merely amount to the direct killing of members of a group. It also includes four other acts which alone, or in combination, constitute genocide under the Convention: causing serious bodily or mental harm, inflicting conditions of life, the forced prevention of births, and forcibly transferring children of the group to another group.

The moral element required for a crime to constitute genocide is the "intent to destroy". There needs to be proof of an intention to destroy one of the groups protected by the Convention "in whole or in part". No specific quantitative threshold is needed for a crime to be qualified as genocide. In consequence, it is the "intent to destroy" which is significant, rather than the actual number of a group who are targeted or killed. In 2004, the International Criminal Tribunal for former Yugoslavia (ICTY) rejected an appeal by General Radislav Krstic, that the numbers killed at Srebrenica (7000 men and boys) were ‘too insignificant’ to be genocide.

Genocide as a criminal act
Under Article 1 of the Convention, genocide constitutes a crime under international law, both in peace or war time, which contracting parties undertake to prevent and punish. Article 3 of the convention lists the five acts that are punishable:

1. Genocide;
2. Conspiracy to commit genocide;
3. Direct and public incitement to commit genocide;
4. Attempt to commit genocide;
5. Complicity in genocide

Persons committing any of these acts shall be punished "whether they are constitutionally responsible rulers, public officials or private individuals" (Article 4). States are required to enact legislation to enable the prosecution of genocide committed on their own territory (Article 5) and to cooperate in extradition where this is necessary (Article 7).

With regard to Article 3, it is important to note that genocide need not have taken place for any conviction to be made. Article 3 elaborates on a fundamental goal of the Convention, to prevent the crime of genocide and thus, legally, charges can be brought against those who have planned, promoted or attempted genocide that did not take place or was thwarted. Presently prosecutions have been focused on those situations where genocide is deemed to have taken place (such as Rwanda) and so the notion of preventive prosecution is an untested one. As the UN steps up its stated desire to prevent genocide and the International Criminal Court (ICC) begins to function, it may be that greater attention is given to such opportunities.

Narrowness of the definition
The definition of the crime of genocide, as upheld in the Genocide Convention, is limited in scope both with regards to the groups and the acts protected by the Convention.

The categories protected under the Convention are limited to national, ethnic, racial or religious groups, therefore excluding other groups such as political opponents and sexual minorities. Acts aimed at the destruction of political opponents, such as those committed by the Khmer Rouge regime in Cambodia, do not fall within the criteria of the genocide Convention, although the targeting and killing of other specific groups under the Pol Pot regime may well match genocide criteria.

The definition of genocide is further limited to the physical destruction of the group, excluding several acts of destruction which are not punishable under the Convention, such as cultural genocide. Cultural destruction of a group may be witnessed in restrictions upon the group, which ban cultural freedoms including traditional practices, ceremonies and events, rights to freely practice religion, or access and rights associated with ancestral lands. Such actions may even be a prelude to physical destruction, which does constitute genocide. However, destruction of culture does not in itself constitute an act of genocide. The only element of the Convention that makes any reference to cultural destruction comes in Article 2(e), which condemns forcibly transferring children of the group to another group as an act of genocide. Actions to destroy the culture of a group outside of this limited reference must be reported or acted against under the provisions and procedures of other human rights instruments, including regional bodies and the International Covenant on Economic, Social and Cultural Rights (ICESCR).

Recent developments
Elements of the Convention, and specifically its definition of the crime of genocide, have been incorporated into the statutes of the two ad hoc tribunals created by the Security Council in 1993 and 1994 - the International Criminal Tribunal for the Former Yugoslavia (ICTY) and the International Criminal Tribunal for Rwanda (ICTR), respectively. The jurisdiction of the Rome Statute of the International Criminal Court (ICC), which entered into force in July 2002, also includes the crime of genocide, and the statute adopts the same definition of the offense as found in the Genocide Convention. Subsequently, references to genocide have been made within United Nations documents, including in the work of expert bodies and special rapporteurs (also see section on International Jurisprudence).