Drone Strikes on Americans Abroad

Per the article posted by MSNBC, Justice department memo makes a case for drone strikes against US citizens abroad that a part of terror groups. I have to admit that I am a bit torn. While Americans are rightfully granted due process, what happens if they are overseas in a third world country that may be hostile to the US, surrounded by armed militants with a known history of aggression towards the US, like Al-Qaida, what do we do then? I don't necessarily want to risk the lives of individuals to get this person, who has pretty much renounced citizenship all but officially if he is plotting against the US, which would be an argument for just bombing. However, this sets a very bad precedent for domestic abuse. I guess I have to side against such actions, barring proof that the person was trying to construct a nuclear weapon or something akin to that.