In fact, officials say, Awlaki did get more due process than most Al Qaeda suspects on the list. They say the administration made a point of naming Awlaki publicly as an Al Qaeda leader — putting him on notice, in effect — before he was killed. And they say the Justice Department held that Awlaki could be killed only if it was not feasible to capture him. The administration has refused to release that legal opinion, in part because it’s not sure it wants those standards to turn into a binding precedent for later cases.

But there are questions that go beyond the legal underpinning for targeted killing. Who puts names on the “kill list,” and who reviews them? And is the process rigorous enough to withstand outside scrutiny?…

That’s one reason some former officials argue that the administration needs to set up a clearer, more rigorous system of internal review — for its own good. John B. Bellinger III, who served as the State Department’s top lawyer during the Bush administration, believes a good solution would be to expand the jurisdiction of the judges who currently authorize wiretaps to cover targeted killing cases as well.

But most intelligence officials hate that idea. “Why on earth would you want to get a judge involved?” asked one. A better solution, he said, would be appointing a special review office made up of seasoned officials who can’t be fired, to insulate them from bureaucratic pressure. But that would still invest life-or-death power in a secret corner of the intelligence community, without a clear constitutional foundation.