Suhail Najim Abdulla Al Shimari and other Iraqi citizens were detained at Abu Ghraib prison (plaintiffs) following the invasion of Iraq in 2003. Al Shimari sued government contractor CACI Premier Technologies, Inc. (codefendant) under the Alien Tort Statute (ATS), claiming that CACI personnel subjected the detainees to inhumane torture and committed war crimes in violation of international law. CACI filed a third-party complaint against the United States (codefendant), alleging that US military personnel ultimately directed the interrogations and torture at Abu Ghraib. The US moved to dismiss on the ground that sovereign immunity barred all CACI’s claims against it. CACI countered that the government waived sovereign immunity for violations of international law considered so fundamental that states may not derogate from them, known as jus cogens norms.