WASHINGTON -- At 12:01 a.m. on Monday, the U.S. government will find itself with fewer tools to investigate terrorism.
The Senate failed to reach a deal to keep provisions of the Patriot Act from expiring before the midnight deadline on Sunday, following a tense political standoff between reform proponents and Senate Republican leadership.
President Barack Obama and government officials spent the last week warning of serious national security consequences, while the most ardent advocates of National Security Agency reform were prepared to call a bluff they saw as little more than fear-mongering.
The Senate is expected to restore the expiring authorities midweek, but here's what we know will change between now and then.
What counterterrorism tools would the U.S. lose if the Senate doesn't act before midnight on Sunday?
The government would lose authorities under three Patriot Act provisions.
The biggest and most controversial is the government's sweeping powers under Section 215 that allow the NSA to collect telephone metadata on millions of Americans and store that data for five years. That will be gone.
Law enforcement officials also won't be allowed to get a roving wiretap to track terror suspects who frequently change communications devices, like phones. Instead, they will need to get individual warrants for each new device.
And third, the government would lose a legal provision allowing it to use national security tools against "lone wolf" terror suspects if officials can't find a connection to a foreign terror group like ISIS, for example. But that provision has never been used, the Justice Department confirmed.
The House overwhelmingly passed a bill, the USA Freedom Act, that would make big changes to the first, but leave the latter two provisions intact.
That bill would have the telephone companies hold Americans' telephone metadata and require the government to get a specific warrant to seize any telephone metadata -- and not on millions of people, but instead on specific individuals.
So those tools would be completely gone on June 1?
FBI and NSA officials would be allowed to continue using Section 215 and the roving wiretap provision in investigations they began before the June 1 expiration date.
Any new investigations would have to go without the roving wiretaps and the ability to petition the secret FISA court -- established under the Foreign Intelligence Surveillance Act to provide warrants in national security cases -- for warrants to seize business records, like telephone metadata, in terrorism cases.
The NSA's bulk metadata collection program would actually end May 31 at 8 p.m. ET to ensure the government is in compliance with the deadline by midnight in military time as well.
The process of winding down that program has been ongoing this week, and the NSA will begin cutting off its connections to telecommunications companies starting at 4 p.m. ET on Sunday.
So could America be less safe on June 1?
Attorney General Loretta Lynch said this week the United States would face a "serious lapse" in national security.
Director of National Intelligence James Clapper said in a statement on Friday the United States "would lose entirely an important capability that helps us identify potential U.S. based associates of foreign terrorists."
But opponents aren't convinced. Instead, they're determined not to let fears over national security trump civil liberties and privacy concerns.
The American Civil Liberties Union said Thursday that "efforts to short-circuit reform efforts should not be allowed to succeed."
"Allowing the provisions of the Patriot Act to sunset wouldn't affect the government's ability to conduct targeted investigations or combat terrorism," the ACLU said. "The government has numerous other tools, including administrative and grand jury subpoenas, which would enable it to gather necessary information."
As it stands, several official review boards -- including a presidential review group and a government privacy oversight board -- found that the bulk metadata collection program was not essential to thwarting a single terror plot.
The Obama administration endorses the plan under the USA Freedom Act to transform that program.
The roving wiretaps provision that can be used in terrorism cases is used less than 100 times per year, but officials would be in a bind when it comes to new investigations. Authorities could still obtain standard wiretaps on a suspected terrorists' phone, but a new phone would require a new warrant.
Officials say the rising threat of lone wolves -- including those inspired by ISIS, but not ordered -- raises the need to maintain that provision of the Patriot Act.
But they concede the provision hasn't yet been used, even as the FBI has increasingly focused its efforts on lone wolves.
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