The United States is not a party to the International Criminal Court and this Article demonstrates that it has a complicated relationship to questions of complementarity in the Rome Statute. Federal and (to a small degree) state criminal law in the United States codifies some of the crimes that, conceptually, relate to conduct proscribed in the Rome Statute, but coverage is incomplete and jurisdiction may often be lacking. Thus, the United States is able to prosecute a limited number of ICC crimes in federal courts as such, particularly genocide, torture, and some war crimes including the recruitment or use of child soldiers. Other crimes might be prosecuted as “ordinary” offenses using statutory provisions on murder, rape, etc. There is no U.S. federal legislation on crimes against humanity, although Puerto Rico has a law criminalizing the same, and legislation has been proposed in the Senate. This existing U.S. law might be sufficient in many cases to permit the complementarity principle to deprive the Court of jurisdiction in cases being investigated or prosecuted by the United States. However, considerable legal gaps in coverage, particularly as regards crimes against humanity, could prevent U.S. courts from exercising criminal jurisdiction over U.S. and foreign nationals accused of committing ICC crimes, particularly given the presumption against extraterritoriality in the application of U.S. federal criminal law, and some have also argued that the military courts martial system may be inadequate to cover the commission of war crimes.

Although it signed the Final Act of the Diplomatic Conference in Rome, and the Clinton administration signed the Treaty in 2000, successive U.S. administrations have had positions ranging from extreme hostility to cautious engagement and none have embraced the Treaty fully. The 2016 Presidential election in the United States may bring additional uncertainty. This uneasy relationship aside, the Department of Justice works to deny safe haven to human rights violators, many individuals are deported from the United States for acts that might be characterized as ICC crimes and U.S. courts routinely cite the Rome Statute as evidence of customary international law in both civil and criminal cases and at least one reported military commission case. Sometimes the United States government is supportive of efforts to combat impunity for the commission of ICC crimes abroad, if it perceives this support to be in the U.S. national interest or strong civil society coalitions among otherwise disparate actors support U.S. action (as in the case of Darfur) emerge. At the same time, there appear to be tremendous political barriers to accountability for the commission of ICC crimes by U.S. persons. For this reason, the United States continues to have an uneasy relationship with the International Criminal Court and is likely to do so for some time.