You could make the argument that targeted strikes authorized by a single person are acceptable in a state of war (which we are not in), but even with that an assassination should have checks on it, always.
Well, I guess it depends on what you mean by a 'check'. I was assuming you meant a congressional panel voting on it or something. If that's not what you mean, and all you meant was some degree of bureaucracy involved, then I think we're in agreement.