UUnder orders from a US appeals court, the Obama administration has released a memo justifying the killing of American citizens with a targeted drone strike. The memo presents a case for killing Anwar al-Awlaki, an al-Qaeda propagandist who was killed in Yemen in 2011. The strike on al-Awlaki has been widely debated since then, especially after a separate attack inadvertently killed al-Awlakis 16-year-old son Abdulrahman.