The concept of an international criminal court has deep a history, with early ideas dating as far back as the 15th century. However, modern international criminal law began to take shape in the aftermath of World War II, when the Allied powers prioritized holding individuals accountable for the atrocities committed by the Nazi regime. 

The establishment of the Nuremberg and Tokyo Tribunals marked a pivotal moment in the development of international criminal law. These post-war tribunals prosecuted major war criminals and set important legal precedents, ultimately leading to foundational treaties such as the Genocide Convention (1948) and the Geneva Conventions (1949).

Though progress stalled during the Cold War, momentum resumed in the 1990s with renewed efforts to establish a permanent international criminal court in response to atrocities in Yugoslavia and Rwanda. In response, the international community created two ad hoc tribunals: the International Criminal Tribunal for the former Yugoslavia (ICTY) and the International Criminal Tribunal for Rwanda (ICTR). Both operated for over 20 years.

The United Nations has emphasized the need for an international criminal court for multiple reasons: to achieve justice for all, to end impunity, to help end conflicts, to remedy the deficiencies of ad hoc tribunals, to take over when national criminal justice institutions are unwilling or unable to act, and to deter future war criminals.

In 1994, the International Law Commission (ILC) drafted a statute for an international criminal court, leading to the 1998 Rome Conference. Despite complex debates, the Rome Statute was adopted in a vote of 120 in favor, 21 abstaining, and 7 opposed.

Official Records of the Rome Conference:

• Final Documents
• Summary Records of the Plenary Meetings and of the Meetings of the Committee of the Whole
• Reports and Other Documents

The ICC was established by the Rome Statute, which was adopted on July 17, 1998, and entered into force on July 1, 2002. The Rome Statute is the foundational treaty that defines the Court's structure, jurisdiction, and functioning. 125 countries are State Parties to the treaty, committing to cooperate with the ICC in its judicial activities.

For more information on the negotiations concerning the Rome Statute:

• The Negotiation of the Rome Statute for the ICC and International Lawmaking in the 21st Century
• Human Rights Watch Overview
• ICC History - The Road to Rome

The United States initially voted against the adoption of the Rome Statute in 1998. Nevertheless, the U.S. signed the treaty on December 31, 2000, under President Bill Clinton.

However, President Clinton expressed concerns and recommended against submitting the treaty to the Senate for ratification until those concerns were resolved. On May 6, 2002, the Bush administration formally notified the United Nations that the U.S. did not intend to become a party to the Rome Statute, effectively "unsigning" the treaty and asserting that the U.S. had no legal obligations arising from its prior signature.

Although the United States is not a member of the ICC, its relationship with the Court has varied across administrations. For a detailed overview, see the timeline tracking the U.S.-ICC relationship over the years.