The possibility of domestic assassinations using drones came up when Brennan first outlined the drone uses overseas. It took Mark's attention to this matter to sound the very appropriate warning. Hears a commentary when the use of drones for assassinations first came up..
Some time before February 2010, the President of the United States authorized the assassination of a U.S. citizen living overseas. The citizen was identified by the White House as a terrorist.
Unlike previous government programs to kill individuals overseas, this one wasn't a covert operation. The program was openly announced, without qualification. Dennis Blair, the Director of National Intelligence, discussed the plan in February at a congressional hearing. A few weeks later, John O. Brennan, the president's National Security Adviser, announced that the marked man was one of "dozens" of U.S. citizens put on the presidential death list because "they are very concerning to us."
The principal of unfettered executive power, absent political and judicial restraint, was officially established. Executive power now supersedes established law.
We have come to the point where the president can openly designate a U.S. citizen as a terrorist removing all rights, including the right to life. The administration implied that this was for overseas targets only. But recall that the illegal wiretapping program was originally for overseas calls only. It rapidly spread to domestic surveillance as well.