In the 1998 case of The Federal Republic of Germany et al. v. United States et al., the German government and two German nationals, Karl LaGrand and Walter LaGrand, sought to prevent their executions in Arizona for a crime they committed while residing in the US as permanent residents. They argued that they were not informed about their right to seek assistance from the German consulate upon arrest, which is guaranteed under Article 36(1)(b) of Vienna Convention on Consular Relations (VCCR). The International Court of Justice (ICJ) issued provisional measures requesting a stay on execution until it could fully consider whether there had been violations of VCCR rights; however, these measures were non-binding and both brothers were executed by Arizona authorities before ICJ reached its decision. This led to further litigation at international level where ICJ ruled that U.S violated VCCR obligations but did not order any specific remedy.

In the dissenting opinion for The Federal Republic of Germany et al. v. United States et al., Justice Stevens expressed concern over the majority's interpretation of international law and its implications on U.S. foreign relations, particularly with respect to extradition treaties. He argued that the court should not have jurisdiction in this case as it involved a dispute between two sovereign nations - Germany and Italy - about their respective obligations under an international treaty, which is typically resolved through diplomatic channels rather than domestic courts. Furthermore, he disagreed with the majority's view that customary international law could be enforced by individual states within their own legal systems without consent from other countries involved in forming those customs or laws; such unilateral action could potentially undermine global cooperation and trust among nations.