A U.S. Congress committee has overwhelmingly approved legislation designed to stop the bulk collection of U.S. phone records by the National Security Agency.

The 25-2 vote in the House of Representatives Judiciary Committee sends the USA Freedom Act to the House floor for a vote. The two votes against the bill came from lawmakers who had argued for stronger protections for civil liberties.

The legislation is a stronger version of a similar bill that passed the House last May but stalled in the Senate, sponsors said. However, several efforts to further strengthen privacy protections by amending the bill failed in committee. Opponents said changes would upend a carefully crafted compromise with House Republican leaders who have threatened to kill an amended bill.

“The USA Freedom Act ends bulk collection, increases transparency and stops secret laws” made in the U.S. surveillance court, said Representative Jim Sensenbrenner, a Wisconsin Republican and primary sponsor of the bill.

The NSA’s collection of huge numbers of U.S. telephone records relies on a “blatant misreading” of the anti-terrorism Patriot Act, added Sensenbrenner, the primary author of that 2001 law. The USA Freedom Act would “reestablish a proper balance between privacy and national security.”

Lawmakers in both the House and the Senate introduced versions of the USA Freedom Act earlier this week. Starting in mid-2013, leaks from former agency contractor Edward Snowden revealed that the NSA has conducted mass collection of U.S. telephone records, but not of the content of phone calls.

The committee struck down a handful of amendments designed to strengthen privacy protections or further limit NSA collection of U.S. residents’ communications or records. A much-debated amendment would have prohibited the FBI and other agencies from searching the content of email messages, text messages and phone calls belonging to U.S. residents when those communications are swept up in a second NSA program targeting foreign terrorists.

That NSA program, separate from its collection of so-called metadata of phone records, allows the FBI access to the content of “tens of thousands” of emails and other communications, said Representative Zoe Lofgren, a California Democrat. The USA Freedom Act is a “vast improvement” over the ongoing NSA phone records program, but “the idea that this bill ends bulk collection … is a fantasy,” she said.

The amendment, offered by Lofgren and Representative Ted Poe, a Texas Republican, would have also prohibited U.S. government agencies from pressuring tech vendors into building surveillance back doors into their products. In recent months, the FBI and other officials in President Barack Obama’s administration have called on tech companies to allow law enforcement access to encrypted communications on smartphones.

The House, last June, overwhelmingly approved a similar amendment in a Department of Defense funding bill, Lofgren noted, although the amendment was stripped out before final approval.

Sensenbrenner and several other committee members voiced support for the ideas in the amendment, but said Republican leaders in the House have promised to kill the USA Freedom Act if it includes language to limit the NSA program targeting the content of messages sent to and from suspected terrorists.

The amendment would be a “poison pill” for the bill at a time when Senate Republican leaders are gearing up to pass an extension to the Patriot Act’s phone records collection program with no new limits, Sensenbrenner said.

Several opponents of the amendment promised to work with sponsors to pass it another way. Backers of the amendment can attach it to “every appropriations bill that comes down the pike,” said Representative Darrell Issa, a California Republican. Under House rules, the chamber’s leaders generally cannot limit the type of amendments offered.

Backers of the amendment complained that the committee was bowing to political pressure instead of protecting U.S. residents’ Fourth Amendment constitutional rights against unreasonable searches and seizures.

The Judiciary Committee needs to uphold constitutional protections, Poe said. “We’re not talking about postponing building a bridge,” he said. “We’re talking about postponing the Fourth Amendment.”

The USA Freedom Act would prohibit large-scale collection of business records from an entire state, city, or zip code. It would also allow businesses who get records requests from the FBI through its national security letter program to challenge orders requiring those businesses to keep quiet.

The bill would also create a new panel of experts at the U.S. Foreign Intelligence Surveillance Court to advise judges about privacy and civil liberties, communications technology, and other technical or legal matters.

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant’s email address is grant_gross@idg.com.