WASHINGTON (CBSDC/AP) — Kentucky Sen. Rand Paul took to the Senate floor Wednesday afternoon to filibuster against the reauthorization of the Patriot Act.

“I’ve just taken the senate floor to begin a filibuster of the Patriot Act renewal. It’s time to end the NSA spying!” Paul tweeted.

Paul — who began the filibuster at 1:18 p.m. ET — told the Senate he “will speak until he can no longer speak.” He held the floor through 11:49 p.m.

“I will not let the Patriot Act, the most unpatriotic of acts, go unchallenged,” he said.

Paul stated that NSA spying has just gotten too big. Republican Senator Mike Lee, of Utah, joined Paul on the floor during the 4 p.m. hour in support of the debate.

“We’ve made the haystack so big no one’s ever getting through the haystack to find the needle,” Paul said.

In March 2013, Paul went on a nearly 13-hour filibuster against the nomination of John Brennan to head the CIA.

Speaking in front of Philadelphia’s Independence Hall earlier this week, the Republican presidential candidate lashed out at the National Security Agency’s bulk collection of American citizens’ phone records, which many in his own party say is needed to prevent terrorism.

“We will do everything possible — including filibustering the Patriot Act to stop them,” Paul said, acknowledging that a filibuster likely wouldn’t be enough to block the program. “They have the votes inside the Beltway. But we have the votes outside the Beltway, and we’ll have that fight.”

The Patriot Act, which authorizes the surveillance program, will expire on June 1 unless Congress acts.

Government surveillance could play prominently in the GOP presidential primary contest, which is heating up just as Congress debates surveillance programs initiated by President George W. Bush’s administration and continued under President Barack Obama.

Supporters of the surveillance law, including presidential candidate Sen. Marco Rubio, R-Fla., say it’s critical to anti-terrorism efforts. Paul and fellow Sen. Ted Cruz, R-Texas, see the law as a privacy infringement.

Neither Wisconsin Gov. Scott Walker nor former Florida Gov. Jeb Bush has yet to take a formal position on the program, although Bush recently praised the Obama administration’s use of big metadata programs that began under Bush’s older brother, former President George W. Bush.

Paul has promised to sign an executive order to end such government surveillance programs on his first day in office, should he win the presidency.

On Monday, Paul said he also opposes a House bill that would end the government’s bulk collection of phone records and replace it with a system to search the data held by telephone companies on a case-by-case basis.Paul said he feared the bill would transfer too much power to phone companies and could jeopardize a related lawsuit.

Paul’s comments on Monday also put him at odds with Senate Majority Leader Mitch McConnell, who has introduced a separate version that would keep the program as is.

“We do not have the votes to ultimately defeat the Patriot Act,” he said. “I can delay it. I can force them to debate it so the public at large can know what they’re doing.”

(TM and © Copyright 2015 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2015 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)