On Tuesday afternoon, a handful of US Representatives will convene to review an amendment that would reauthorize warrantless foreign surveillance and expand the law so that it could include American citizens. It would, in effect, legalize a surveillance practice abandoned by the NSA in 2017 in order to appease the Foreign Intelligence Surveillance Court, which found the NSA to have abused its collection capacity several times. If it passes Tuesday’s review, the bill may be voted on by the US House of Representatives as early as Thursday.

Drafted by the House Intelligence Committee last December, the FISA Amendments Reauthorization Act of 2017 is an amendment to Section 702 of the Foreign Intelligence Surveillance Act (FISA). It is one of six different FISA-related bills under consideration by Congress at the moment, but by far the most damaging to the privacy rights of American citizens.

FISA was enacted in 1978, but Section 702, referred to by former FBI Director James Comey as the “crown jewels of the intelligence community,” wasn’t added until 2008. This section allows intelligence agencies to surveil any foreigner outside the US without a warrant that the agency considers a target. The problem is that this often resulted in the warrantless surveillance of US citizens as well due to two loopholes known as “backdoor searches” and “about collection.”

Backdoor search refers to a roundabout way of monitoring Americans’ communications. Since intelligence agencies are able to designate any foreigner’s communications as a target for surveillance, if this foreigner has communicated with an American this means this American’s communications are then also considered fair game for surveillance by the agency.

So-called “about collection” makes the warrantless surveillance of US citizens by intelligence agencies even easier.

As revealed by Edward Snowden's leaks in 2013, the NSA uses Section 702 to monitor internet communications in two ways: “upstream” and “downstream.” According to the NSA, downstream collection—also known as PRISM—works by picking a target selector (say, a particular email address) and monitoring communications to and from that selector. So if an American citizen were to email a foreign-targeted email address, that American’s communications would be subject to surveillance as well.

Read More: James Clapper Finally Admitted the NSA Used PRISM to Spy on US Citizens

Upstream collection, of which about collection is one component, allowed the NSA to monitor any communications to, from, or about a target selector. In other words, if a particular foreign email address is being targeted by the NSA and that email address is even mentioned in an electronic communication by an American, then their communications can be collected, even if that American wasn’t in contact with the foreign target.

“Backdoor search and about collection take something that's supposed to be a foreign intelligence authority focused on counterterrorism and turns it into a warrantless, domestic law enforcement surveillance authority,” Jake Laperruque, senior counsel at the Project On Government Oversight told me on the phone.

Last April, the NSA announced it would be discontinuing certain upstream collection activites after the Foreign Intelligence Surveillance Court deemed it illegal. The NSA has been repeatedly chastised by the courts for failing to stay within the outlined limits of the program.

The new House Intelligence Committee amendment to section 702 would reverse this decision and allow about collection by law. This would, in effect, allow the warrantless surveillance of Americans’ communications, even if that American isn’t suspected of breaking the law.

Section 702, which was authorized in 2008, was set to expire on December 31, 2017. Yet Congress was unable to reach an agreement on the terms of its reauthorization so its expiration was pushed to January 19. If the House Intelligence 702 amendment passes a vote this week, it will still have to pass the Senate, where a nearly identical bill has been drafted by the Senate Intelligence Committee.

“If the House approves the bill, then I think the FBI will really see this as a green light to take these controversial practices and ramp them up to an unprecedented degree,” Laperruque said.

A number of bipartisan opposition efforts to the intelligence committee bills have emerged. If the House Intelligence bill doesn’t pass, there is another Section 702 amendment called the USA Liberty Act proposed by the House Judiciary Committee. This bill has been criticized by civil rights groups like the Electronic Frontier Foundation for falling short of meaningful surveillance reform, but it would still be a win for Americans’ privacy compared to the Intelligence Committee amendments.

The strongest challenge to the House and Senate Intelligence Committee bills is the USA Rights Act, a bipartisan bill sponsored by Senator Rand Paul and Ron Wyden. Widely supported by civil rights groups, the USA Rights Act would require strong oversight of intelligence agencies by an independent agency, close the backdoor loophole by requiring a warrant to search the communications of US citizens, and codify the illegality of about collection.

Laperruque said he’s optimistic there’s enough resistance to these bills to force Congress to do a temporary reauthorization of Section 702 without any changes while they have a real debate about how to reform US surveillance practices.