Among many of his Republican colleagues, Senator Rand Paul is, for now, Enemy No. 1.

The Patriot Act is (at least temporarily) dead, and his fellow Republicans are blaming the Kentucky senator for the problem. He is grandstanding for political purposes, they say—and endangering national security in the process.

For a major Republican presidential candidate, Paul has certainly alienated a lot of Republicans—especially hawks who believe in strong surveillance authorities for the intelligence community. Or, you might think, Paul has carved out a unique segment in the GOP field.

After midnight on Monday, three major surveillance provisions contained within the Patriot Act expired. Paul took procedural steps to block any faster consideration of the USA Freedom Act, which would have continued but reformed those provisions.

“I don’t stand with Rand,” Republican Senator Mark Kirk told The Daily Beast, flipping Paul’s campaign slogan. “I disagree with him. I think we should not allow the program to be interrupted.”

In a rare Sunday night vote for the Senate, called in a foiled attempt to address the issue before the Patriot Act provisions expired, fellow Republicans laid into Paul.

“I just saw a tweet from Senator Paul saying, ‘Take a selfie of yourself when you’re watching me on the floor tonight.’ In case you missed it, take a look at it,” Senator John McCain, the chairman of the Senate Armed Services Committee, said dismissively. (McCain later joked, “I’m not good-looking enough to enjoy that.”)

“Unfortunately I think it’s part of the presidential campaign,” said Senator John Cornyn, the No. 2 Republican in the Senate. “This really does raise the risk to the public. It does eliminate one of the tools that the intelligence community has to identify homegrown terrorists. It just seems to me at least reckless to not allow at least a temporary continuation of the bill while we have this debate. But that’s not the way it’s working.”

Paul insiders insist that there was no political calculus behind Sunday’s event, but nevertheless demand anonymity when describing this matter of conscience.

“There are certain things that are a matter of principle,” one senior Paul adviser told The Daily Beast. The adviser added that even if Paul did believe his opposition to NSA spying might negatively impact his success in the Republican presidential primary, that wouldn’t have stopped him from blocking the measure.

The three provisions that expired at midnight include Section 215, which was the legal basis for the NSA’s bulk collection of metadata; the provision on roving wiretaps; and a section authorizing surveillance against so-called lone wolves.

But Paul’s actions won’t have lasting effect, from the perspective of the law.

While the authorities are expiring, the expectation is that the Senate will return later this week to reauthorize sections of the Patriot Act, albeit with reforms and restrictions outlined in the House-passed USA Freedom Act. In the meantime, backdoor provisions and alternate collection schemes will allow U.S. spies to continue surveilling important targets.

Politically, that might not matter.

The fact is, Paul killed controversial parts of the Patriot Act—bumper stickers aren’t big enough for the details about how long their death lasted.

“We should not be debating modifying an illegal program,” Paul wrote in an op-ed for Time on Saturday. “We should simply end this illegal program.”

As he spoke on the Senate floor, Paul tweeted, using the hashtag #endNSAspying—and, at least once, #endNSA, something he said earlier in May he does not want to do. Paul’s supporters sent him words of encouragement: “Keep it up! We are listening!” They also sent photos of themselves watching his speech on the Senate floor. The process even yielded some “#babiesforRand.”

Paul’s human-roadblock strategy has its benefits: It puts him in the spotlight fighting a battle in which he has remained consistent throughout his political career. And perhaps more important than that, the burst of attention comes both after a period of doubt among some of Paul’s more staunchly libertarian supporters and, conveniently, while he is promoting his latest book.

Over the past year, as Paul has traveled the country campaigning, a central question has followed him: to what degree will he sacrifice the “libertarian-ish” principles that took him from his Bowling Green ophthalmology practice and into the United States Senate in order to appeal to the broader GOP electorate?

Senator Paul would not exist without the supporters he inherited from his father, Ron Paul, but he has let them down with his compromises, like signing the Iran letter and voicing his support for the Obama administration’s drone policy.

Paul’s opposition to the Patriot Act, despite the risk it carries, is a nod to those supporters that he is not leaving them behind, not that he could afford to lose them.

Paul’s surveillance-ending stunt places him happily in opposition to the Obama administration and his rivals in the Republican primary field. Chris Christie, Jeb Bush, and Marco Rubio favor a robust metadata collection program. Ted Cruz was an early co-sponsor of the USA Freedom Act, which would reform the Patriot Act and end the government’s bulk collection of American metadata.

“I recognize that there is nothing you very kind folks in the media like more than Republican-on-Republican violence. You would like me to say something negative about my friend Rand, but I have no intention of doing so,” Cruz told reporters Sunday night.

That said, Cruz opposes Paul’s actions in the Senate, which forced the (brief) expiration of surveillance authorities.

“I disagree with allowing key provisions of federal law to expire that allow the national security team to target radical Islamic terrorists,” Cruz said.

Back in November, Paul and Cruz battled over the USA Freedom Act, with Paul ultimately winning when the bill was defeated. The measure didn’t go far enough to fix the problem, Paul argued. Cruz countered that to fix the problem, you had to do it from within the existing system.

But Paul may now be politically vulnerable. Were a national security issue to arise, his critics could argue he was the roadblock to preventing the act’s passage. It’s a vulnerability he acknowledges.

On the Senate floor, he suggested, “Some of them, I think, secretly want there to be an attack on the United States so they can blame it on me.”

—With additional reporting by Alexa Corse.