The principles of extraterritorial jurisdiction under international law allow States to assert legal authority over their citizens abroad on the basis of nationality. Conceptions of nationality, however, have become blurred. Individuals are more mobile than ever before. They can live and work in different parts of the world. They may have a connection to more than one State. Similarly, serious crimes, such as acts of terrorism, need know no national boundaries, and armies can attract foreign recruits. Some States, such as Australia and the United Kingdom, have responded to their citizens serving as foreign recruits by legislating to allow for the revocation of citizenship. This has produced a burgeoning literature on citizenship-stripping in an age of heightened security risks. However, none of the analysis has considered the questions from the perspective of the principles of extraterritorial jurisdiction and the power of the State over its nationals when abroad. This chapter reconsiders the legitimacy of States relying on assertions of extraterritorial jurisdiction to deprive citizenship. The chapter argues that it is an abuse of rights. If a State can assert its rights over citizens abroad, then a State is violating its responsibilities for its nationals under international law by removing those citizens from its realm of responsibility.