Senator Rand Paul speaks to guests at a campaign event at Bloomsbury Farm on April 25, 2015 in Atkins, Iowa.National Journal

The Senate is going on vacation, but it didn't finish its homework.

With no solution in sight to the Patriot Act quagmire that kept lawmakers voting until past 1 a.m. Saturday, senators have left town for a week. They will return next Sunday—just hours before the deadline to act on the future of the federal government's sweeping domestic-spying powers.

In a tense vote after midnight, the Senate failed to move forward on the House-passed USA Freedom Act, legislation that would end the National Security Agency's bulk collection of call data. The vote was 57-to-42, just short of the 60-vote threshold needed after stiff opposition and last-minute whipping Friday night into Saturday from Majority Leader Mitch McConnell and other GOP defense hawks. Senators then easily rejected a motion to move ahead on a McConnell-backed two-month extension of the Patriot Act's spying authorities.

If the two high-stakes votes at 1 a.m. weren't enough, the dramatic scene that followed showed how tense things are in the Senate.

McConnell proposed an even shorter-term extension of the surveillance authorities—from their current June 1 expiration date through June 8, giving the Senate time to take its Memorial Day recess before returning to take up the issue once again. Sen. Rand Paul objected on grounds he wanted up-or-down votes on his amendments to the Freedom Act, and what followed was an unusual exchange between McConnell and pro-reform senators that resulted, where much of the night did, in no solution.

McConnell suggested putting off the debate until June 5, earning objection from Sen. Ron Wyden of Oregon. Then McConnell tried for June 3, to the objection of Sen. Martin Heinrich of New Mexico. Finally the majority leader asked for an extension through June 2. Paul objected again, and the Senate took another short break.

A flushed McConnell attempted to figure out his next move, while Paul—the junior senator from Kentucky who's using his NSA stand to promote a presidential run—strolled around the perimeter of the chamber, hands tucked into his suit pockets.

On Twitter, he celebrated: "Patriot Act filibuster successful and ongoing. Bulk phone-record collection set to expire."

After meetings on the Senate floor, McConnell announced the Senate would try again on May 31, hours before the program is set to expire. Senators will have "one more opportunity to act responsibly," said a visibly flustered McConnell.

Minority Leader Harry Reid took a thinly veiled jab at longtime rival McConnell, casting blame on how the new majority leader crunched the schedule by spending weeks on a trade agreement that lacks a firm deadline.

"That's what happens when you try to jam everything in just a short period of time," Reid said. When asked if anything would change next Sunday, Reid said, "I don't know, you'll have to ask Rand Paul [and] the Republicans."

Paul's answer to the same question of what would change in a week?

"It depends, sometimes things change as deadlines approach," Paul said as he quickly walked down the Capitol's marble steps and into a car waiting for him outside.

Sen. Angus King, a Maine independent, said there may be a better chance for progress after some time off. "We have to refocus on the fact that this is an important program, that this is an extraordinarily dangerous time, and it's on us to find a solution," King, who voted against the Freedom Act, said. "There are some... there are some steps that need to be taken before next Sunday, but I don't think there will be any breach in the program."

Republican Sen. Mike Lee, a cosponsor of the Freedom Act, criticized the delay in bringing up the bill until Friday night. "I think we should have done that at the beginning of this week. This was an entirely avoidable scenario," Lee said. "I think we should have put it on the floor earlier. It was a big mistake not to."

But even if the Senate reconvenes on Sunday and manages to pass legislation pushing back the expiration, members of the House have promised to not let anything through but the Freedom Act, a measure that passed the lower chamber overwhelmingly last week.

The House won't reconvene from its current Memorial Day recess until the evening of June 1—after the provisions will expire. Rep. Justin Amash, a Michigan Republican and one of Congress's most strident critics of the Patriot Act, vowed late Friday to block any unanimous-consent deal that would allow the House to agree to any clean short-term extension that the Senate might pass.

Amash was sitting on the side of the Senate chamber Friday evening along with Rep. Thomas Massie, a Kentucky Republican. During the Patriot Act votes, Paul could be seen chatting and laughing with the pair of civil libertarians.

After the sequence of votes, Amash celebrated on Twitter with an #ExpireThePatriotAct hashtag.

All this is the culmination of a week of Senate drama, including Paul's "filibuster" on Wednesday afternoon. The GOP presidential candidate promised Friday to reporters and on Twitter to continue blocking efforts to extend the Patriot Act's spy provisions, a pledge that comes as a second act to his 10-and-a-half-hour floor takedown of government surveillance earlier in the week.

"Will be seeing everyone overnight it seems," Paul tweeted earlier Friday evening. "My filibuster continues to end NSA illegal spying."

During a lag in between votes on the fast-track trade bill earlier Friday, Paul and McConnell talked one on one briefly in the middle of the Senate floor as other lawmakers chatted around them. Their conversation appeared congenial, but Paul soon walked away and exited to chamber. Minutes later, his Twitter account announced his holdup, and McConnell announced a delay on the floor soon after to a vote that would happen after midnight.

Republican Sen. Dean Heller, a cosponsor of the USA Freedom Act, admitted that Paul is getting on the nerves of his fellow senators.

"It's causing some frustration for some members," Heller told reporters. "Sen. Paul is going to do what Sen. Paul wants to do, and everyone lets him do it. Sometimes it looks more like presidential politics than anything else."

"He has a position, he has a point," he added. "We don't disagree with him, but there are probably other ways he could be effective, or more effective."

Sen. John McCain wasn't happy, either. "There's a new breed in the Senate and we have seen the manifestation of it, of people who are willing to, one or two or three, are willing to stand up against the will of the majority," McCain said. "Some time ago, the Senate could sit down and try and work things out."

Majority Whip John Cornyn refused to criticize Paul's maneuver, saying that a senator's "greatest tool is to object to unanimous consent."

During his first objection, Paul said he was blocking McConnell's short-term extensions because he wanted a simple-majority vote on two of his proposed amendments to the Freedom Act. Paul said he thought that was a fair compromise from a starting point of the six amendments he had been seeking, which Republican leadership said would have required 60 votes.

Paul outlined his amendment demands during his talkathon on Wednesday. His edits to the House bill would prohibit the government from mandating that tech firms create so-called surveillance "backdoors" in their products, which the NSA could access. They would also close a loophole that allows backdoor searches, referring to the NSA's practice of searching through foreigners' data to "incidentally" collect information on American citizens who correspond with the targets.

Paul also wants a "constitutional advocate" to be present in order to argue against the government in the FISA Court, and he wants to expand protections on customers' data held by third-party companies such as Google or Facebook.

Other proposals would require courts to approve national security letters to "make them more like warrants," allowing for American citizens to appeal surveillance orders handed down by the FISA Court, and implement limitations to the Reagan-era Executive Order 12333, which some privacy advocates say allows the NSA the majority of its spying power.

Before Friday night's session, McConnell's office was telling lawmakers that supporting the USA Freedom Act would mean they would have to stay in town longer—a pitch made during an afternoon meeting with much of the Republican caucus.

"McConnell and his staff forcefully made the case that a vote for USA Freedom was a vote to cancel recess," a Republican aide said.

Now, they will have their break, but still have work left to do.

This story has been updated.

Rachel Roubein, Brendan Sasso, and Sarah Mimms contributed to this article

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