With about 45 days remaining before a major post-9/11 surveillance authorization expires, representatives of the National Security Agency and the FBI are taking to Capitol Hill to convince legislators to preserve their sweeping spy powers.

That effort effectively re-inaugurates a surveillance debate in Congress that has spent much of 2015 behind closed doors. Within days, congressional sources tell the Guardian, the premiere NSA reform bill of the last Congress, known as the USA Freedom Act, is set for reintroduction – and this time, some former supporters fear the latest version of the bill will squander an opportunity for even broader surveillance reform.

Republican leaders of the House intelligence committee arranged for NSA and FBI representatives to hold secret briefings for members of Congress on Tuesday and Wednesday. Staff did not name the officials addressing legislators.

The classified briefings come amid an unsettled surveillance debate in Congress that rushes up against an unforgiving deadline. On 1 June, Section 215 of the Patriot Act, which permits US law enforcement and surveillance agencies to collect business records, expires.

Section 215 is the authority claimed by the NSA since 2006 for its ongoing daily bulk collection of US phone records revealed by the Guardian in 2013 thanks to leaks from whistleblower Edward Snowden. While the Obama administration and US intelligence agencies last year supported divesting the NSA of its domestic phone metadata collection, a bill to do so failed in November.

But the FBI and its supporters fear that the expiration of Section 215 will cut deeper than the loss of bulk collection. The FBI is warning that it will lose access to investigative leads for domestic terrorism and espionage, such as credit card information, hotel records and more, outside normal warrant or subpoena channels.

While the briefings were not described as a platform for defending the controversial Section 215, they “offer an important opportunity to hear directly from analysts and operators who use Section 215 as part of their daily mission to protect the Nation from terrorist attacks,” according to an announcement for legislators sent by intelligence committee chairman Devin Nunes and Georgia Republican Lynn Westmoreland and obtained by the Guardian.

Civil-libertarian members who attended left unsatisfied.

“Our questions about constitutionality and legality were answered with statements of efficacy. We said, ‘How can this possibly be legal?’ and they would say, ‘this program works great, here’s how it’s helping us catch terrorists,’” Representative Thomas Massie, a Kentucky Republican, told the Guardian.

Yet with Section 215’s lifespan now stretching to a matter of weeks, supporters of broad surveillance powers have yet to put forth a bill for their preservation – evidence, opponents believe, that the votes for reauthorization do not exist, particularly not in the House of Representatives.

Members of the intelligence and judiciary committees in both chambers are still negotiating behind closed doors to determine the shape of a vehicle to reauthorize 215. A spokeswoman for Senator Richard Burr, the North Carolina Republican who leads the Senate intelligence committee, had no information to offer on Tuesday. Senator Dan Coats, an Indiana Republican, left an afternoon intelligence committee meeting saying the shape of a reauthorization was under “ongoing discussion”.

A different congressional source said Senate GOP leadership was “clinging to the pipe dream” of a straight reauthorization.

More likely, according to a multiple Hill sources, is a different option under consideration: making the major NSA reform bill of the last Congress the point of departure for reauthorizing 215 in the current one.

That bill, the USA Freedom Act, passed the House in May 2014 before narrowly failing in November in the Senate. Belatedly, the White House endorsed it, after seeing it had a greater chance of passage than any pro-NSA alternative. Yet the House version lost substantial civil-libertarian support after the intelligence agencies and House leadership weakened its surveillance restrictions, including its central prohibition on the bulk collection of domestic phone records.

Advocates of the bill in both congressional chambers, including its original architects, have been laboring for eight weeks in marathon negotiations to revive the USA Freedom Act. The revived bill would extend the expiring provisions of the Patriot Act for a still-undetermined number of years – essentially staking out the center of the 2015-era surveillance debate for a bill that would take NSA out of the domestic bulk-collection business.

Advocates believe they are close enough to agreement that reintroduction could come as early as Thursday and would move through the judiciary committees.

But several privacy activists inside and outside Congress consider the USA Freedom Act insufficient.

The bill would not abridge NSA collection of Americans’ international communications, nor prevent the NSA or the FBI from warrantlessly searching through its troves of them for Americans’ identifying information. Nor would it restrict a constellation of surveillance efforts authorized by a Reagan-era executive order. Even a recently disclosed bulk domestic phone records collection dragnet by the Drug Enforcement Agency would be untouched.

“We should be demanding more reforms than the intelligence agencies are gladly willing to offer us,” said David Segal of the activist group Demand Progress.

Last month, Massie co-sponsored a bill introduced by Wisconsin Democrat Mark Pocan going much further. The Surveillance State Repeal Act would repeal the entire Patriot Act and a landmark 2008 expansion of the Foreign Intelligence Surveillance Act. As well, the bill carries protections for national-security whistleblowers against retaliation and makes probable cause the basis for foreign-intelligence surveillance of an American or someone on US soil.

But the bill, with only ten current co-sponsors, faces questions about its viability, which even Massie concedes.

“It’s very long odds, but it’s a statement about what needs to happen. It’s a stronger Freedom Act that’s not going to get watered down,” Massie said.

After the NSA briefing on Tuesday, Massie said he sees a “tremendous opportunity” for surveillance reform, and said he thinks the newest members of Congress are likely to determine the fate of the expiring Patriot Act provisions.

“A lot of it is going to hinge on the freshmen. Right now, as far as I can tell, the select intelligence committee is making a real strong play to persuade the freshmen that all of these public concerns are overblown,” Massie said.





Ben Jacobs in Washington contributed reporting.