The International Court of Justice (ICJ) and the International Criminal Court (ICC), both headquartered in The Hague, are the authoritative bodies set to investigate possible crimes by Israel and hold the culpable parties accountable.
With the two world courts working to stop attacks targeting civilians in the Gaza Strip and punish those responsible, here’s a rundown of their roles, powers, differences and prominent features, which will loom large if the responsible parties are called to the docket to face justice.

International Court of Justice (ICJ)
The ICJ, the primary judicial organ of the UN, was established in June 1945 and commenced activities in the Peace Palace in The Hague, the administrative capital of the Netherlands, in April 1946.
Among the core tasks of the Court are resolving legal disputes between states in accordance with international law and providing advisory opinions on legal issues referred to it.
Exclusively dealing with disputes between states, the Court consists of 15 judges, jointly elected for nine years by the UN General Assembly and the Security Council.
The expenses of the Court are covered by the UN.

International Criminal Court (ICC)
Established as an independent and permanent criminal court based on the Rome Statute of 1998, the ICC prosecutes individuals who commit genocide, crimes against humanity, war crimes and aggression.
The Court, headquartered in The Hague and operational since 2002, exclusively tries real persons, including heads of state and high-ranking government officials.
While 18 judges are elected for a term of nine years to the ICC, the expenses of the Court are covered by contributions from member countries and donations from third countries.

Cases that can be opened in the ICJ
Cases in the ICJ are opened depending on the subject matter of international treaties in which states are in dispute. The cases typically involve sovereignty, border disputes, maritime disputes, trade, natural resources, violations of human rights treaties and disputes related to the interpretation of treaties.
In addition to issuing binding decisions resolving disputes between states, the ICJ can also provide non-binding advisory opinions on matters requiring expertise in international law.

Crimes investigated by ICC
The Rome Statute, which established the ICC, specifies four crimes that the court can prosecute: genocide, crimes against humanity, war crimes and crimes of aggression. Any crime outside the four categories is not within the jurisdiction of the Court.
The first three crimes were detailed in the Statute in 1998, while the crime of aggression was defined after the Kampala Conference in 2010.

Who can bring cases to the ICJ and ICC?
In the ICJ, only states have the right to bring contentious cases, and potentially all 193 UN member states can appear before the court.
Individuals, non-governmental organizations, companies, or other private entities cannot be parties to a case in the ICJ.
If a state appears before the ICJ on behalf of one of its nationals against another state, it remains a dispute between states.
UN entities, with relevance to the scope of their activities and organs, can seek advisory opinions from the ICJ on matters related to international law. States cannot request advisory opinions.

Advisory opinions not binding
The authority to initiate cases in the ICC lies solely with the Office of the Prosecutor.
While states or individuals generally submit complaints to the prosecutor, the decision to open a case is at the discretion of the prosecutor, subject to approval by the Court.
There is the possibility to appeal to the Pre-Trial Chamber of the Court against the prosecutor's decision to open or not open a case.

How cases are initiated in ICJ

The ICJ does not have the authority to prosecute individuals accused of war crimes or crimes against humanity.
As the ICJ is not a criminal court, it does not have a prosecutor who can initiate trials. The ICJ also lacks the power to take the initiative in handling a dispute, and it can only address a dispute if one or more states request its intervention.
For

the ICJ to have jurisdiction, states involved in the dispute must accept the Court's jurisdiction, meaning they must consent to the ICJ handling the particular dispute. States can express consent in three ways.
Firstly, two or more states with a dispute on a particular matter can agree through a special agreement to submit the dispute to the ICJ.
An example is the case involving Hungary and Slovakia related to the Gabcikovo-Nagymaros Project, which was heard in the ICJ based on a specific agreement between the two countries.
Secondly, many international treaties include provisions where states commit to accepting the ICJ's jurisdiction in case of a dispute about the interpretation or application of the treaty.
Today, there are clauses in more than 300 multilateral treaties empowering the ICJ. The basis for the ICJ hearing South Africa's case against Israel was the authorization of the ICJ to resolve disputes under Article 9 of the Genocide Convention.
Thirdly, states can unilaterally declare their acceptance of the ICJ's jurisdiction in all cases involving other parties. While 74 states have made such declarations acknowledging the ICJ's jurisdiction, the Court can exercise its general jurisdiction in disputes only when all parties are among the 74 states.
An example is the case concerning the land and maritime boundary dispute between Nicaragua and Honduras in the Caribbean Sea, which was initiated in this manner.
In cases brought before the ICJ, unless the defendant state objects to jurisdiction, the Court does not inquire whether jurisdiction exists.
If the defendant state does not raise an objection to jurisdiction, it is assumed implicitly that the state accepts the Court's jurisdiction, and the judgment becomes binding.
In the Corfu Channel case between Albania and the UK, Albania effectively acknowledged jurisdiction by not objecting to the Court's authority.

Initiation of cases in ICC
The ICC prosecutor can initiate investigations in three ways.
Firstly, the prosecutor can initiate an investigation proprio motu for crimes committed by any person within the territory of a state party or crimes committed globally by a national of a state party. For example, the ICC Prosecutor initiated an investigation proprio motu for crimes against humanity committed during internal turmoil in Kenya after the 2007 and 2008 elections.
Secondly, the prosecutor can initiate an investigation based on requests from states. The request may come from states that are parties to the ICC, or even non-party states based on the temporary and limited jurisdiction under Article 12(3) of the Rome Statute. The investigations into crimes in Palestine and Ukraine were initially opened under Article 12(3), and later both states became parties to the ICC.
Thirdly, the ICC Prosecutor can open cases related to situations referred by the UN Security Council. In contrast to the other two methods, cases referred to the ICC Prosecutor by the UN Security Council are binding on all UN member states under Chapter VII of the UN Charter and do not require the consent of the referred state. Investigations into Libya and Sudan in the ICC were initiated based on resolutions from the Security Council.



How is genocide regulated in international law?
The term "genocide" was first introduced into international documents with the 1948 UN Convention on the Prevention and Punishment of the Crime of Genocide.
Article 2 of the Convention includes the following:
"In the present Convention, 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."
The definition of genocide in the Genocide Convention is also explicitly used in Article 6 of the Statute of the International Criminal Tribunals for Rwanda and the former Yugoslavia, as well as in Article 6 of the Rome Statute, the founding treaty of the International Criminal Court (ICC).
A crucial element in establishing the crime is the determination of the perpetrator's "genocidal intent," which involves actions carried out to destroy, in whole or in part, a particular group solely based on membership in the group.