The U.S . can lawfully kill an American citizen overseas if it determines the target is a "senior, operational leader" of al-Qaeda or an associated group and poses an imminent threat to the country, according to a Justice Department document published by NBC News.
The document defines "imminent threat" expansively, saying it does not have to be based on intelligence about a specific attack since such actions are being "continually" planned by al-Qaeda.
"In this context," it says, "imminence must incorporate considerations of the relevant window of opportunity" as well as possible collateral damage to civilians. The document also provides a legal rationale behind the Obama administration's use of drone strikes against al-Qaida suspects.
Exactly what constitutes an "imminent" threat is not specifically defined, however.