The GOP presidential hopeful joins Democrat Ron Wyden in threatening to block a bill reauthorizing the Patriot Act without NSA reforms.
Sen. Rand Paul is squarely staring down congressional leadership over surveillance reform.
The Kentucky Republican said Monday he would filibuster any attempt to reauthorize the sections of the Patriot Act that allow the National Security Agency to run its mass data-collection programs.
"I'm going to lead the charge in the next couple of weeks as the Patriot Act comes forward," Paul told the New Hampshire Union Leader. "We will be filibustering. We will be trying to stop it. We are not going to let them run over us."
With the filibuster threat, Paul placed himself in direct opposition to Senate Majority Leader Mitch McConnell, who proposed reauthorizing the Patriot Act without any changes. Paul was initially quiet after McConnell, his fellow Kentucky Republican, floated reauthorization last month.
And his threat was the second such declaration in two days: Democratic Sen. Ron Wyden of Oregon said this weekend that he would filibuster a straight reauthorization of the Patriot Act—even if it's just a short-term extension of the law.
"If they come back with that effort to basically extend this for a short term without major reforms like ending the collection of phone records, I do intend to filibuster," Wyden told MSNBC on Sunday.
A spokesman for Wyden said Paul's filibuster threat makes it "clear there is a growing bipartisan coalition to stand up to any reauthorization of Patriot Act Section 215 that does not end bulk collection and make major reforms."
Wyden and Paul, both privacy hawks, are longtime critics of the NSA's surveillance programs. Wyden supports the USA Freedom Act, a proposed bill which would end bulk collection of U.S. phone records, although he says he'd like the legislation to go further to curtail surveillance.
Paul, however, voted against a version of that bill last year, because he said it was too weak. He's indicated opposition to the bill in this session, most recently in an op-ed in which he suggested the effort could "actually gave new authority to the Patriot Act to collect records."
The House will vote on the USA Freedom Act on Wednesday, and is expected to pass it easily. The Senate has only 10 legislative days left before parts of the Patriot Act sunset on June 1.
A surveillance-themed filibuster would not be Paul's first takeover of the Senate floor. In 2013, Paul stood on the Senate floor and spoke for almost 13 hours during the nomination of John Brennan for CIA director, in response to the agency's drone program.