More than three dozen privacy and civil rights groups are pushing Congress to consider changes to the 2001 anti-terrorism Patriot Act as lawmakers move to renew provisions that expire in December.

Section 215 of the Patriot Act is one of the provisions due to expire without action from Congress. It allows the FBI to ask for a court order to obtain “any tangible things,” including books, records, papers, and documents, related to a terrorism investigation, and it served as the foundation for the National Security Agency’s massive collection of telephone records for several years.

Thirty-nine groups have signed on to a recent letter to Congress asking lawmakers to consider limiting large-scale collection of data by the NSA, saying the 2015 USA Freedom Act has not achieved its goal of preventing bulk surveillance. In 2017, the NSA collected 534 million telephone records, three times the number collected in 2016, the groups noted, citing data from the office of the director of national intelligence.

On March 28, a bipartisan group of lawmakers introduced the Ending Mass Collection of Americans’ Phone Records Act, which would permanently end mass phone records collection at the NSA. The bill is “the opening bid in a much-needed, broad overhaul” of Section 215, said Sen. Ron Wyden, D-Ore., a sponsor of the bill.

The NSA reportedly suspended the controversial telephone metadata collection program in late 2018, but privacy advocates worry that the agency could resurrect the practice using Section 215 as the legal foundation. Their main complaint is that the NSA has, through bulk records collection, swept up the personal records of millions of innocent people.

[ Opinion: The NSA stopped collecting bulk phone data, and nothing bad happened]

“Congress should formally remove the NSA’s ability to collect Americans’ telephone records on an ongoing basis, including the ability to collect records of individuals who are not under suspicion,” said Andrew Crocker, senior staff attorney at the Electronic Frontier Foundation, one of the groups that signed the letter. “We want to ensure that bulk or large-scale collection truly ends.”

Congress should also look at whether the law should continue to allow the NSA to collect “any tangible thing” related to an anti-terrorism investigation, Crocker added. Privacy advocates have complained that “any tangible thing” gives the NSA excessively wide-ranging surveillance authority.

Revelations by former NSA contractor Edward Snowden “focused attention on the NSA’s tortured interpretation of ‘relevance’ to collect telephone records which it knew to be mostly irrelevant, but defenders of civil liberties and civil rights have worried about the ‘tangible things’ language right from the start,” Crocker wrote in a recent blog post.

“Even if Congress entirely outlaws the most well-known use of Section 215, the government will still have the authority to collect ‘any tangible thing’ based on a very loose relevance standard.”

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Formally ending the call records collection program would be a good “first step,” added Sharon Bradford Franklin, director of surveillance and cybersecurity policy for the Open Technology Institute at New America, another group signing the letter. Lawmakers should also narrow the way the NSA can conduct searches, and it should prohibit searches based on race, religion, and other “discriminatory” identifying characteristics, she said.

She predicted some momentum in Congress for changing Section 215 after the reports of 534 million call records collected in 2017. The NSA’s announcement last June that it was deleting hundreds of millions of call records because of “technical irregularities” also raises questions about Section 215 programs, she added.

With Section 215 expiring in December, Congress will need to take action or let the surveillance programs revert to a much more limited, pre-Patriot Act state, Crocker said. “That alone should be incentive for the intelligence community to come to the table,” he added.

The director of national intelligence didn’t respond to a request for comment on the recent letter to Congress. The letter, organized by the American Civil Liberties Union, was also signed by the Council on American-Islamic Relations, conservative advocacy group FreedomWorks, the NAACP, and TechFreedom, a libertarian-leaning think tank, among others.

While the Democratic majority in the House of Representatives may be sympathetic to changing Section 215, major reform may be tougher to pass in the Senate. Senate Majority Leader Mitch McConnell, R-Ky., has long advocated for extensions of Section 215 without changes. McConnell’s office didn’t respond to a request for a comment on the coalition letter.