Sen. Patrick Leahy (D-Vt.) introduced a new compromise version of the USA Freedom Act in the Senate on Tuesday, aimed at curtailing the government surveillance and data collection practices revealed by former National Security Agency contractor Edward Snowden.

"If enacted, this bill would represent the most significant reform of government surveillance since Congress passed the USA Patriot Act 13 years ago," Leahy declared on the Senate floor. "It's a historic opportunity." Leahy had joined Rep. Jim Sensenbrenner (R-Wis.), author of the USA Patriot Act, in introducing the original version of the legislation last year.

"This is a debate about Americans' fundamental relationship with their government -- about if the government should be able to create massive data bases about its citizens or about if we are in control of our own government, not the other way around," Leahy said.

The legislation would curb bulk collection of domestic phone records, provide new transparency measures and add an adversarial component to the Foreign Intelligence Surveillance Court.

The Senate bill would replace bulk collection with the ability to collect call record details within two hops on a daily basis when the government can demonstrate a "reasonable, articuable suspicion" that search terms are associated with a foreign terrorist organization under section 215 of the Patriot Act. This would limit the government from being able to broadly collect information by geographic region, such as by Zip code or area code, which critics feared might be the case in the version of the Freedom Act that passed the House earlier this summer.

That House version was altered after it was passed out of committee, prompting many privacy advocates to pull their support from the bill and half of the legislation's House sponsors to vote against it on the floor. "Though clearly intended to end bulk collection," Leahy argued that this version did not do so effectively.

Leahy's new version of the Freedom Act would require the government to report how many individuals' information has been collected under certain surveillance authorities and how many of those are likely Americans -- as well as the number of queries run on Americans in some data bases, with exceptions for figures not possible to generate with current technology. It also expands how private companies can publicly report on government requests for information.

Additionally, the bill requires the FISA Court to appoint a panel of special advocates to support privacy and civil liberties arguments in its proceedings.

Sensenbrenner endorsed the new compromise version, saying in a statement that it "strengthens the privacy protections of the House bill while retaining support from the Administration and intel community." He also noted that the changes from the version passed by the House had regained the support of some privacy groups and technology companies.

"If Congress passes this version of the USA Freedom Act, it would be a historic win for Americans’ privacy and civil liberties, but Congress’ work on surveillance reform has only just begun," said Kevin Bankston, the policy director at New America's Open Technology Institute.

Harley Geiger, senior counsel at the Center for Democracy and Technology, took a similar position, calling the bill a step in the right direction. However, Geiger said in a statement, "there are many issues related to overbroad national security surveillance that this bill does not address, such as reform of surveillance under Section 702 of FISA and Executive Order 12333, and the undermining of encryption standards.”