Regardless of whether this US citizen is killing other citizens, they are afforded protections from the Constitution and amendments. If the administration feels it is proper to target this person for elimination, then they should first go through the process of either revoking citizenship or trial in-absentia with a guilty conviction and a death sentence. To once again kill an American citizen without due process and a conviction is a blatant abuse of power and is wholly unconstitutional - regardless of how right the action may be.