Rand Paul
Sen. Rand Paul, a Republican from Kentucky and 2016 U.S. presidential candidate, speaks during a campaign event in Davenport, Iowa, May 28, 2015. Daniel Acker/Bloomberg via Getty Image

WASHINGTON -- Rand Paul is sticking to his fight against the Patriot Act, and it looks like he'll prevail. The law, which allows the government to collect large quantities of phone data from American customers, expires on Sunday. The deadline is forcing the Senate into an unusual weekend session to try to find a resolution.

Obama administration officials have spent the last week offering dire warnings that if the program isn’t renewed, American security is at risk. (It probably didn't help their case that the New York Times published an editorial Thursday opposing the bulk collection of phone records.)

The Senate tried -- and failed -- last week before leaving for the Memorial Day weeklong recess to allow two different bills that would renew the Patriot Act to move forward. Unless the Senate, which returns May 31, agrees to pass a House bill that Senate Majority Leader Mitch McConnell doesn't support -- and Paul agrees to speed up the required time between votes, which is highly unlikely -- the surveillance program will expire. Capitol Hill aides concede an expiration is almost certain.

The House isn’t due back to hold votes until Monday at 6:30 p.m., which means that even if the Senate were to find compromise on a new bill, the House couldn’t consider it until hours after the deadline.

Attacking the Patriot Act is a key issue for presidential candidate Paul. The Kentucky senator is at odds with his own party and has drawn criticism from fellow Republicans that he is putting the nation at risk. Paul spent much of the week touring the nation to promote his new book and making campaign appearances in early primary states. Along the way, he has vowed to keep up his fight. In an appearance on MSNBC’s “Morning Joe,” Paul blamed the growth of the Islamic State group on arms sales backed by Republican party hawks -- a view that angered other GOP hopefuls and renewed criticism that he is an isolationist like his father, former congressman Ron Paul.

When he takes to the Senate floor on Sunday, Paul won’t have to launch a multi-hour speech to kill the program. It will require simply saying “I object” a few times. But Paul will be saying a lot more with those words -- hoping to breathe more excitement into his campaign and invigorate the libertarians who make up his base.

The super PAC backing Paul’s presidential bid released a video to hype the Sunday night vote. The video -- complete with bald eagles, flames and an Photoshopped image of Paul that shows him as a shirtless man with rippling muscles -- sets the vote up as a fight between Paul and President Barack Obama, who the super PAC argues is aligned with Texas Sen. Ted Cruz.

McConnell has minimal options. Senate rules require days of debate to complete passage of a bill, a process that is normally sped up by having the agreement of all the members. But one objector can slow everything down.

The House already passed the USA Freedom Act, a bill that would renew the Patriot Act but make changes to the way the government tracks phone data. Instead of being permitted to round up the records of millions of phone calls, the phone companies would keep the information and the government would have to obtain it from them. If the Senate passed this bill, it would head straight to Obama -- who indicated he would sign it.

Paul is against the Freedom Act in its current form. He wants stronger protections that require search warrants for individuals -- not for entire phone companies -- in order for the government to obtain records. He wants the ability to hold votes on amendments to the bill. But so far, McConnell hasn’t agreed to those votes.

Complicating the matter, the Freedom Act doesn’t have the strong support of McConnell, who would rather renew the program as it exists now. McConnell brought forth a bill that would do exactly that. That bill also failed last week to get the votes needed to clear a procedural hurdle.

McConnell will try again on Sunday night. He will offer both the Freedom Act and the Patriot Act complete renewal. There are no indications that either bill will gather the needed votes.