I'm certainly not an advocate of freewheeling assassination by the state, but the issue does get murky remarkably quickly. are things like the Phoenix Program, McChrystal's JSOC command, the drone campaign, legitimate or quasi-legitimate outgrowths of war (leaving aside the question of whether those wars were a good idea in the first place - which, in the cited cases, no)? I'm inclined to say no, tho I think there's an argument to be made, as someone did, that targeted assassination is preferable to, say, bombing (Reagan's of Gaddafi, missing the man himself but killing 60-odd other people, comes to mind). the thing is, how are assassinations different/worse from non-targeted killings? I understand your larger point about the rule of law, but it seems that nations & individuals tend to follow or ignore the IHL as is most convenient. and when have Americans ever really cared about the rule of law or due process when it did was an obstacle to their goals? like many things, they are "cherished [nationality] values" mostly when it is expedient.
to clarify, before I get jumped on - I'm not saying this isn't an outrage. but really, is it so much more outrageous b/c this dude's an American citizen, or b/c Jose Padilla was, & so on?