"I will speak until I can no longer speak," Paul began Wednesday morning, at 11:47 a.m. "I cannot sit quietly and let [the President] shred the Constitution."

It didn't end until 12:39 a.m. Thursday morning, when he wrapped up to thunderous applause.

"I discovered that there are some limits to filibustering, and I'm gonna have to go take care of one of those in a few minutes," Paul said.

Paul became the first Senator to use the "talking filibuster" in more than two years. He was joined several of his Senate colleagues around the three-hour mark, and the group had grown to 13 Republicans and one Democrat — Sen. Ron Wyden — by the end of the filibuster.

Paul's marathon remarks focused on violations of civil liberties under the Obama administration, and particularly on a letter sent by Attorney General Eric Holder this week, which claimed that the President has the legal authority to use military force against American citizens on U.S. soil.