I wonder whether the current kerfuffle over whether there was a legal obligation to invite OBL to surrender would be different had the Obama administration, and John Brennan and Eric Holder in particular, not inexplicably displayed a certain hesitation on the question of capture versus kill.
Suppose that faced with that initial, and entirely predictable, question — did the SEALs attempt to capture Bin Laden? — Brennan had instead brooked no opposition and snapped back with visible irritation —
of course they were not attempting to capture him, they were there to attack and kill him, to attack him with lethal force. This was an armed lethal attack upon a a criminal adversary of the United States in an armed conflict, without cavil or apology. They were sent to attack and kill him as someone who was targetable with lethal force and no warning at any time. Which, as explanations go, and (at least as it appears at this particular moment) does have the virtue of being true, as well as legally sound.
Brennan's response was weak - he's not the legal counsel, after all - but Holder's was also weak. Particularly as differing accounts have dribbled out, the administration has found it surprisingly hard simply to say (with apologies to Mary Ellen O'Connell), it is not law enforcement, and of course it was legal to target OBL, legal to target with lethal force, legal to target without warning or invitation to surrender, and that has always been the US legal position. I don’t understand how this entirely obvious question wasn’t briefed and anticipated, with an answer directly from Harold Koh’s 2010 American Society of International Law address on exactly this point:
Some have argued that the use of lethal force against specific individuals fails to provide adequate process and thus constitutes unlawful extrajudicial killing. But a state that is engaged in an armed conflict or in legitimate self-defence is not required to provide targets with legal process before the state may use lethal force ....
The principles of distinction and proportionality that the US applies are … implemented rigorously throughout the planning and execution of lethal operations to ensure that such operations are conducted in accordance with all applicable law ....
Some have argued that our targeting practices violate domestic law, in particular, the longstanding domestic ban on assassinations. But under domestic law, the use of lawful weapons systems — consistent with the applicable laws of war — for precision targeting of specific high-level belligerent leaders when acting in self-defence or during an armed conflict is not unlawful, and hence does not constitute ‘assassination’.