Rand Paul is on the Senate floor right now filibustering the renewal of the Patriot Act

Senator Rand Paul (R-Kentucky) is currently on the Senate floor filibustering the renewal of a controversial American national security program.

On Wednesday afternoon, Paul began filibustering the renewal of the Patriot Act. Passed in the wake of the September 11 terrorist attacks, the Patriot Act has been broadly used to justify controversial national security programs including the National Security Agency's bulk collection of American's telephone metadata.

Paul has been an outspoken critic of the act. The Republican presidential candidate has repeatedly said that the NSA data collection program justified under the act is unconstitutional. In 2014, Paul sued the Obama administration over this, claiming that the NSA was violating Americans' 4th Amendment rights by not obtaining a warrant before collecting telephone metadata.

Paul has not given an estimate on how long the filibuster could last, but he said that he would do "whatever it takes" to stop the reauthorization of the Patriot Act.

"Well, nobody can predict how long you can talk, but I plan on doing everything humanly possible to try to stop the Patriot Act," Paul said, according to CNN.

The Senator is no stranger to the filibuster. In 2013, Paul spent 13 hours on the Senate floor filibustering Central Intelligence Agency Director John Brennan's confirmation to protest the US drone program.

Paul said that the notoriety of that filibuster brought him fans, who now ask him what else he'll filibuster.

"People are always asking, 'Are you going to filibuster this or filibuster that?'" Paul said during a forum in Philadelphia, according to the LA Times. "To my mind, there are few times when something rises to the occasion that is so important that you really have to take a stand on that issue."