"It's not just power corrupts, but that 'absolute power corrupts absolutely'," Paul said. "I think people can become intoxicated with power. I don't know if that's the explanation for President Obama's about-face. He was one, when he was in this body believed, in some restraint."

But Paul did not endure the filibuster by himself. At three hours and 10 minutes, he began sharing his time with other Republican senators, Mike Lee of Utah, Ted Cruz of Texas, Jerry Moran of Kansas, Marco Rubio of Florida, Saxby Chambliss of Georgia, John Cornyn of Texas, John Barrasso of Wyoming, John Thune of South Dakota, and Pat Toomey of Pennsylvania, who each weighed in with questions and their own commentary.

"I would note that your standing here today like a modern Mr. Smith Goes to Washington must surely be making Jimmy Stewart smile," Cruz said to Paul. His appearance represented his first time to speak on the Senate floor. "And my only regret is that there are not 99 of your colleagues here today standing with you."

Cruz noted that Wednesday marked the anniversary of the fall of the Alamo in San Antonio, Texas. Comparing the fight to Paul's effort on the Senate floor, Cruz said "Texans are proud" to see Paul (a native Texan) standing up "for liberty."

He then read a famous letter--perhaps in a move to kill time -- from William Barret Travis in 1836, asking for more back-up at the Alamo.

Cruz, talking to Paul, said he hopes the "glorious letter give(s) you encouragement and sustenance on this 177th anniversary on the Alamo."

At just over four hours, the filibuster took an interesting twist when a Democratic senator, Ron Wyden of Oregon, came to the floor to assist and make the stand-off a bipartisan effort.

It's important to note that the drone controversy is one of the few issues where the far right and the far left sync up. While Wyden said he wants to make his point about the targeted killing of Americans by drones, he said he will still vote for Brennan at the end of the day. He did so in the Senate Intelligence Committee.

"Senator Paul and I agree that this nomination also provides a very important opportunity for the United States Senate to consider the government's rules and policies on the targeted killings of Americans," he said.

At just around five hours into the filibuster, Senate Majority Leader Harry Reid came to the floor to gauge whether or not the Senate could hold a vote on Brennan Wednesday night.

He tried to limit the remaining time for debate to 90 minutes, but Paul objected, saying he wants answers from Holder that clarify his remarks on drones Wednesday morning.

Reid said he can't speak for the administration and canceled his request, meaning there would be no full vote on Brennan Wednesday.

The filibuster had its light-hearted moments, as well. When Rubio stepped up to join the filibuster, he had some words of wisdom for Paul.

"I know you've been here awhile. Let me give you some advice -- keep some water nearby. Trust me," Rubio joked, poking fun at his now-famous sip of water during the middle of his Republican response to the president's State of the Union address last month.

Around 7:30 p.m. ET, Cruz returned to the floor to read aloud tweets about Paul's filibuster.

"I think the technical term for what the Twitterverse is doing right now is called 'blowing up'," Cruz said, highlighting the slogan -- "Stand with Rand" -- that's spreading online.

In the ninth hour, Lee again took over the spotlight so Paul could have a break. While the senator from Utah was speaking, Paul chatted with House members and paced back and forth in between the Senate desks. Since beginning the talking filibuster shortly before noon, he has not sat down or taken a bathroom break.

Well into the 11th hour, Rubio returned and at one point started quoting the musical artist Jay-Z.

A short time later, Senate Minority Leader Mitch McConnell came to the floor to express his support for the effort.

"At whatever point we get to a cloture vote to extend debate on the nomination of Brennan, it is my view that cloture should not be invoked. This is a controversial nominee. Should cloture be invoked, I intend to oppose the nomination and congratulate my colleague from Kentucky for this extraordinary effort," McConnell said.

And with midnight quickly approaching, Paul's support from his colleagues only seemed to be intensifying. Republican members of Congress began gathering in the Senate chamber in solidarity. And at 11:47 pm Republican National Committee Chairman Reince Priebus tweeted an all-call to Republican senators who aren't already on the floor:

"Attention all Republican US Senators -> Please go to the floor and help out @SenRandPaul #StandWithRand."

Paul continued to talk so he wouldn't have to relinquish the floor, but he did not have to stay on the floor to keep his filibuster going. Although he was drawing attention to his objections to the administration's drone policy, senators are not required to be on the floor to block a vote, unlike previous times.

So what would have happened if Paul had kept going?

At some point, Reid was expected to make a parliamentary move that would start the clock ticking for a vote to break the filibuster. Sixty votes would have been needed to break the filibuster, and as Paul himself has acknowledged, he didn't have the votes to succeed.