UPDATE: NBC's Michael Viqueira is reporting Attorney General Eric Holder the day after the filibuster sent a letter to Senator Paul writing, "Does the president have the authority to kill an American not engaged in combat on American soil? No."
WASHINGTON (AP) - A Republican senator from Kentucky used an old-style filibuster to take control of the chamber and block Senate confirmation of John Brennan's nomination to be CIA director.
Sen. Rand Paul ended his 13-hour filibuster Thursday shortly after midnight, but Senate Minority Leader Mitch McConnell said he would continue to oppose Brennan's confirmation and resist ending the debate on President Barack Obama's pick to lead the spy agency.
Paul's performance, which centered on questions about the possible use of drones against targets in the United States, energized a number of his GOP colleagues, who joined him on the floor in a show of support.
Actual talking filibusters have become rare in the Senate, where the rules typically are used in procedural ways to block the other party's agenda.
(CNN) -- The White House has reached out to Sen. Rand Paul after he spent thirteen hours on the Senate floor demanding answers from President Barack Obama's administration on the use of drones against American citizens, the Kentucky Republican said Thursday.
"We want the president to respond. And what we're hearing from the White House is they may respond to my question," Paul told CNN Chief Congressional Correspondent Dana Bash in an exclusive interview Thursday. "If they do, we're willing to let the Brennan nomination go forward."
Paul's filibuster stalled a vote on Obama's CIA director-nominee John Brennan, who was a top architect of the administration's drone program.
Pressed for more details on his communications with the White House, Paul said he didn't have the name of which official had reached out, but did say that "somebody on my staff and other Republican staffs are talking to the White House."
And he added that Obama and he could have more in common on the issue than it may appear.
"When Barack Obama was a senator, I think he would have been standing with me last night," Paul said. "I think he, like [Democratic Sen. Ron] Wyden, would have come to the floor and supported me yesterday. I think he's either forgotten or needs to be more explicit in what his beliefs are."
The decision to take to the Senate floor with his questions on drones was a last minute one, Paul said, explaining he hadn't come completely prepared to remain standing for thirteen hours straight.
"We had no plan and I had the wrong shoes on, my feet were hurting the whole day," Paul said, explaining that since the Senate leadership typically decides who speaks on the Senate floor, it's often difficult to begin a traditional filibuster.
"One of the reasons filibusters don't occur is because they carefully guard the floor from letting it happen. And it was left unguarded," he said.
His voice was recovering from his epic floor remarks, Paul said, though he got a break from a bevy of Republican senators (and one Democrat) who joined in during the day. And he speculated he may have "lost a few pounds" by only eating an occasional candy bar - which cameras caught him noshing on throughout the day.
"There's a candy drawer, and if you go to the candy drawer, you can sneak around and get a candy bar. But I see you caught me with half the candy bar in and half out of my mouth. My wife said can't you chew with your mouth closed on the floor?"
The grueling conditions are all part of the rules of a traditional filibuster, which Paul admitted were demanding.
"It's not easy. My feet were hurting by the end of the day. You can't leave the floor and you can't sit down. So you can't use the restroom or do anything like that," he said, admitted the staff in the chamber are often more knowledgeable about restrictions than lawmakers themselves.
One of his tips? "I decided to drink very little water and have no caffeine."
Paul hasn't been without his Republican critics, including the conservative editorial page of the Wall Street Journal, which Thursday urged him to "calm down."
"The U.S. government cannot randomly target American citizens on U.S. soil or anywhere else," the paper's editorial read.
"The Wall Street Journal is right on a lot of issues and they're wrong on this issue," Paul responded in his CNN interview. "The problem is if I call you an enemy combatant, how do we know if you are or aren't? That's just me calling you and accusing you of a crime."
"Should there be enough power by any politician, Republican or Democrat, to just say you're an enemy combatant and a hellfire missile drops on your house?" he asked. "That's what they're saying. With every fiber of my body, I believe that's unjust and unconstitutional."
CNN's Kevin Liptak contributed to this report.