Eric Holder responds to Rand Paul's filibuster with this letter:

Dear Senator Paul:  It has come to my attention that you have now asked an additional question: "Does the President have the authority to use a weaponized drone to kill an American not engaged in combat on American soil?" The answer to that question is no.  Sincerely,  Eric Holder

Here's an image of that letter:

UPDATE: Apparently, the White House and Justice Department failed to send the letter to the person who asked the question--Rand Paul.

Spox for Sen. Rand Paul on Holder: "We haven't received any letter yet."

— Sabrina Siddiqui (@SabrinaSiddiqui)
March 7, 2013

More Rand Paul spox on Holder letter: "Apparently he sent it to everyone except the man who asked the question."

— Sabrina Siddiqui (@SabrinaSiddiqui)
March 7, 2013