Attorney General Eric Holder has written a letter to Sen. Rand Paul (R-Ky.) saying that a drone could not be used against a noncombatant American. In response, Paul has said he the Senate should move ahead with John Brennan's nomination as director of the CIA. The vote is being held this afternoon.

The letter followed a 13-hour filibuster of Brennan by Paul and several other senators, who objected to the possibility of domestic drone strikes on U.S. citizens.