> Sure, but while arrest and criminal prosecution may be more problematic (though not impossible) with a foreign citizen in a foreign country, extrajudicial killing is generally less problematic there, largely for political reasons (and, in large part, as a consequence of the perception that arrest and criminal prosecution is more difficult.)

Yes, that's a good point. Even with some form of executive due process it will never be likely that foreigners abroad have more or equal Constitutional protections than citizens on U.S. soil, and the NSA could tie back into that.