That and several other key provisions in the underlying law, the Patriot Act, expired June 1. So in a rare Sunday session, the Senate advanced a new bill eventually ending the NSA's bulk collection of our phone calls and requiring the government to first get a warrant to search for any individual records, which will be held by the phone companies.
It's been a messy debate made more complicated by a fight from Paul: The Kentucky Republican and 2016 presidential hopeful slowed down final passage of the bill until Tuesday because he said the pending legislation didn't go far enough to protect our privacy. So Congress went home Sunday night without a final deal approved and left a giant question mark over what the NSA can do now.
Among those questions: Are we less safe because of what happened yesterday? Safer? Here are six things you need to know about the debate:
1. This was the first time Congress has openly debated bulk collection of our phone records.
We may not have been having these conversations today if former NSA contractor Edward Snowden hadn't shared classified information that showed that the government was collecting our phone records -- and much more -- with the world in 2013.
It's hard to say what would have happened with the Patriot Act reauthorization deadline if we didn't know what we know now: President Obama had set up an independent group to study the 2001 program before the Snowden leaks.
But it's safe to say we wouldn't have had a Republican presidential candidate making this once-secret program a major pillar of his campaign and filibustering the program on the Senate floor.
2. Now that the news it out there, Congress has three options.
- Extend the law untouched. Senate Majority Leader Mitch McConnell (R-Ky.) and Obama administration officials such as CIA Director John Brennan support this path, saying American lives depend on the tools in the Patriot Act.
- Approve a compromise delicately mapped out by privacy advocates, members of Congress and Obama administration officials. The USA Freedom Act would take six months to phase out the NSA's automatic collection of our call records, including their time, date and duration. After six months, the law would require the agency to get a subpoena from a court to look at phone companies' records for a specific call log.
- Find some sort of other deal that makes privacy advocates and libertarians like Paul happy.
After weeks of vociferous debate about what to do, senators agreed to move option two forward 77 to 17 on Sunday. The House of Representatives had previously passed the measure with more than 300 votes.
3. It's unclear how the NSA is operating now.
The New York Times spoke with intelligence officials who said there are several workarounds possible over the next few days (or weeks) when the NSA doesn't have power to collect Americans' phone records.
Three provisions that expired — allowing the bulk collection of phone records, the ability to investigate "lone wolf"American terrorists and the ability to investigate suspects who switch phones — have grandfather clauses that let any investigation started before June 1 continue indefinitely.
But the Obama administration has said it won't use this grandfather clause to continue the collection of our phone records — they'll let Congress figure out what should be done.
That means while Congress decides what to do, we can be pretty sure the NSA is no longer logging the metadata of every phone call we make.
4. So, are we less safe now because of that?
The Obama administration certainly think so.
"We will experience a serious lapse in our ability to protect the American people," Attorney General Loretta Lynch warned in the week leading up to the deadline.
So do Republican hawks like McConnell, who say the USA Freedom Act doesn't do enough to protect Americans. (And, of course, even the USA Freedom Act isn't law yet.)
But two independent reviews of the bulk-collection program found no evidence that the program had stopped a specific terrorist attack. A bipartisan one Congress set up in 2007 — before the Snowden leaks — said the program's most significant accomplishment was helping the FBI analyze a man in San Diego who had donated money to a Somali terrorist group. He was not convicted of anything, according to Charlie Savage of The New York Times.
NSA supporters respond that it's impossible to measure success when success is defined as nothing happening.
Bottom line: In Americans' years-long conversation about where to find the sweet spot between privacy and security, it seems our country has yet to settle on a consensus.
5. In Congress, the battle's not over, either.
Nowhere is that uncertainty more amplified than in Congress.
The Senate will vote on final passage of the USA Freedom Act on Tuesday. But that leaves two days for lots of changes to the bill, which could significantly slow down (or stop) its path to the president's desk.
Paul said the compromise doesn't do enough to protect privacy. McConnell says it doesn't do enough to protect our safety. Ninety-eight other senators have their own opinions.
McConnell has filed amendments that would lengthen the time it takes for the NSA to phase out automatically collecting our phone records from six months to a year. If the Senate passes something like that, it would have an uphill battle in the House, and this whole process could drag on for weeks.
6. Rand Paul upset pretty much everyone in Congress — and he's happy about that.
This story begins and ends with Rand Paul, because he's the major reason Congress let the program lapse Monday.
He's declaring victory for his stated mission to end the phone record collection program.
But it's a symbolic one, because Congress is moving forward with an NSA reform bill Paul doesn't agree with, Bloomberg's David Weigel points out.
The fight left Paul without many friends in the Senate, as he clashed with McConnell — a clash made all the more remarkable by McConnell's endorsement of Paul for president.
But Paul doesn't mind. He's sending out fundraising e-mails on his "victory," supporters wearing "Stand with Rand" T-shirts filed in and out of the U.S. Capitol on Sunday night to support him, and he's successfully cemented himself as the anti-NSA candidate in a crowded Republican field.
Here's Paul in his own words: "As we move forward, the Patriot Act will expire tonight. It will only be temporary. They will ultimately get their way. But I think the majority of the American people actually do believe the government has gone too far."
The question for Paul is whether a majority of Republican primary voters agree with him.