Privacy advocates, facing an uphill battle in a Republican-controlled Congress next year, will have to make a difficult choice.

Some argue that their best shot to curb the National Security Agency's powers will be to kill core provisions of the USA Patriot Act altogether. But other reformers aren't ready to take the post-9/11 law hostage.

The debate over whether to let the Patriot Act provisions expire in June threatens to splinter the surveillance-reform coalition. If the tech industry, privacy groups, and reform-minded lawmakers can't coalesce around a strategy soon, they may have little hope of reining in the surveillance state.

And with outrage over the Snowden revelations fading and fear over the Islamic State rising, the push for reform appears to have already lost its momentum.

The NSA critics are still licking their wounds after Senate Republicans blocked the USA Freedom Act last week. The bill, authored by Senate Judiciary Committee Chairman Patrick Leahy, would have prohibited the government's carte blanche collection of U.S. phone metadata—the numbers and time stamps of phone calls but not their actual contents.

The bill would have also extended key provisions of the Patriot Act for two years, including the controversial Section 215, which the NSA uses to justify its phone-record collection program. But that wasn't enough for Minority Leader Mitch McConnell, Sen. Marco Rubio, and most members of the Republican Caucus, who warned that the bill would have helped terrorists kill Americans.

"This is the worst possible time to be tying our hands behind our backs. The threat from ISIL is real," McConnell said in a statement, using an alternative name for the Islamic State.

With the Republicans winning the Senate, McConnell is about to become the majority leader, giving him control over the chamber's agenda. Given his aggressive last-minute whippingagainst the Freedom Act, privacy advocates say it is difficult to imagine him pushing anything more than cursory changes to the NSA.

But with so many ways to block legislation in Congress, it's always easier to stop something than to pass it. That reality has already led some privacy advocates to want to kill any reauthorization of the Patriot Act that doesn't include substantial reforms to the government's spying powers—a viewpoint that has already spawned a #Sunset215 hashtag.

They're hoping to use the leverage of the looming deadline to at least force the Republican leaders to offer up some real changes.

"It looks like the Republican leadership in the Senate is very resistant to any reform, and that is true in the House as well," said Rep. Zoe Lofgren, a leading advocate of surveillance reform.

But, she argued, the rank-and-file members in both parties remain deeply skeptical of NSA spying.

"The leaders want one thing, and the members want another," the California Democrat said in an interview. Lofgren argued that to secure enough votes to renew the Patriot Act provisions, congressional leaders will have to include a package of reforms. While she thinks that blocking the reauthorization should be on the table, she warned that it would still leave other NSA abuses unaddressed.

Sen. Ron Wyden, an Oregon Democrat, also said he wants to use the looming Patriot Act deadline as leverage for stronger changes.

"The June expiration of several of these provisions gives both sides of this debate a strong incentive to come to the table and finally end overreaching programs that violate the privacy of millions of Americans without making our country safer," he said in a statement.

But not everyone who has called for limits on NSA spying is ready to let the Patriot Act expire.

Rep. Jim Sensenbrenner, the chief author of the original Patriot Act, became a sharp reform advocate, arguing that the NSA is abusing the law. And in the past, he has repeatedly warned that Congress might block a reauthorization bill that doesn't rein in the agency.

But with the deadline fast approaching, Sensenbrenner, who also authored the original draft of the Freedom Act, appears to be shying away from that all-or-nothing rhetoric.

"While it's possible those on the privacy side of the debate will opt for sunsets and those on national security side will leverage turmoil in Middle East, Congressman Sensenbrenner will continue to push for sensible reform," an aide to the Wisconsin Republican said in a statement. "Reform is necessary, but what it will look like is uncertain."

The tech industry appears reticent to jeopardize the Patriot Act renewal, too. Facebook, Google, and other Silicon Valley giants have been valuable partners in the anti-surveillance movement, arguing that NSA spying hurts their business. But those companies may be reluctant to attach their names to any effort to let legislation expire that the intelligence community claims is vital to national security.

Jessica Herrera-Flanigan, a lobbyist for Reform Government Surveillance, a coalition of tech companies, argued that the reformers can get more Republican support just by going through the traditional committee process. It's too soon to give up on the Freedom Act and focus on killing the Patriot Act, she said.

"We should start with [the Freedom Act] because it has consensus around it," she said. "We should not start from scratch."

No one in the NSA reform coalition thinks letting Section 215 sunset will solve all of their concerns about government surveillance. But privacy advocates generally see its expiration as a useful bargaining chip, and, if neither side blinks, a worthwhile step forward.

Tech and many pro-reform lawmakers, however, may find that too risky a gamble.

Leahy, the author of the Freedom Act, didn't say which side of the debate over the Patriot Act renewal he will fall on.

"The bill I proposed was a good bipartisan bill," Leahy told reporters in the Capitol last week. "People are going to wish they had that this time next year."

(Image via Rena Schild / Shutterstock.com)