The killing of Anwar Al-Awlaki and another U.S. citizen by airstrike in Yemen, although never officially attributed to U.S. military action, has fuelled the on-going debate about the legal propriety of targeted killings, in particular where a U.S. citizen is targeted or killed. While the Obama Administration has not released a detailed description of the legal rationale undergirding the targeting policy, some insight into the Administration's thinking can be gleaned from speeches given by high-ranking Administration officials and government filings in a legal case brought by Awlaki's father in an effort to enjoin military operations against his son. This book examines the debate concerning legal targeting of U.S. citizens suspected of terrorism, by providing legal background, setting forth what is known about the Administration's position and identifying possible points of contention among legal experts and other observers, including the view from abroad.