A surveillance law that allows U.S. intelligence agencies to collect the communications of foreign targets abroad without a warrant is set to expire at midnight on Friday, prompting warnings from current and former officials that a lapse could endanger national security.

The immediate effect of allowing Section 702 of the Foreign Intelligence Surveillance Act (FISA) to expire would be limited. That’s because a judge on the Foreign Intelligence Surveillance Court renewed the government’s surveillance certifications in March, allowing intelligence agencies to continue using the authority until March 2027. 

But supporters of the law say a lapse risks creating uncertainty for the government and the companies it relies on to provide information. If Congress has not renewed the law by 2027, they argue, the government could lose access to one of its most important intelligence-gathering tools.

Critics, however, contend that the warnings overstate the immediate risk and obscure the reason the law has become so politically contentious: Section 702 is aimed at foreign targets abroad, but it has been used to search Americans’ communications collected in the course of that surveillance.

Why are officials calling for Section 702 to be extended?  

Glenn Gerstell, a former general counsel of the National Security Agency (NSA), tells TIME the risk of a lapse should not be dismissed. Crucially, he explains, the intelligence acquired through Section 702 makes up roughly 70% of the President's daily brief. 

“In other words, it covers everything from sanctions evaders, to narco-terrorists, to ISIS terrorists, to what Iran might be up to, North Korea, etc,” he says during a phone interview. “So it's probably the critical national security tool. So if it lapses, it stands to reason that we'd be worried about what we're missing.”

Technology companies would also become more reluctant to comply with government requests, he argues, in particular if they fear violating privacy agreements or being sued. This resistance, he says, could slow the collection of intelligence and create gaps.  

“[Companies] want to make sure that they're not going to get sued if they go ahead and comply with a court order,” he explains. “The question is, what are we going to be missing in that period of time—during the time of litigation, whether it's three days or six weeks … it only takes one small piece of information about a terrorist plot or a sanctions evader or a North Korean missile to have a potentially profound effect on national security.” 

Republican lawmakers have also issued similar warnings.

Secretary of State Rubio and Defense Secretary Pete Hegseth urged Democrats on Monday to support an extension, with Rubio warning that allowing the spy powers to lapse would be “devastating to our national security.” 

In a letter to Rubio, Sen. Chuck Grassley of Iowa and Sen. Tom Cotton of Arkansas urged the Secretary of State to “plan for a potential significant gap in foreign intelligence collection” if Section 702 expired. 

“Letting 702 lapse is a real gamble that we can’t afford to take,” Grassley said while speaking on the Senate floor on Monday. “Let’s be very clear: if Section 702 lapses, our adversaries will benefit greatly, and Americans will suffer.”

A White House official told TIME in a statement on Wednesday that “the Administration always recognized this would be a complex issue which is why negotiations continue with Congressional Members to find long-term consensus.”

“The Administration strongly supports full reauthorization to allow us to gather foreign intelligence, and protects our country from malign actors,” the official added.

A group of former intelligence officials, which included Gerstell, earlier called on Congress to reauthorize the law.

"We cannot afford to let our Intelligence Community lose this tool that helps keep our nation safe, even for a day,” the group wrote in April. 

Why lawmakers want Section 702 reformed

But critics of Section 702 say the warnings overstate the immediate threat because the current certifications will remain in effect until 2027. They have pushed for Congress to use the coming months to impose new limits on the program, including a requirement for the government to acquire warrants before accessing Americans’ communications incidentally collected through the surveillance program. 

The current process for FBI searches of Section 702 data using U.S.-person query terms requires internal approval, and two rounds of internal audits would follow, according to a watchdog report. Although Section 702 prohibits direct spying on Americans, some communications between U.S. citizens and foreigners will be incidentally collected, which the FBI is allowed to retain and later look into. Some lawmakers have argued that the internal signoffs are not enough to place a check on the executive branch’s power. 

“Congress should not give Donald Trump, Stephen Miller, and Kash Patel unchecked power to spy on Americans,” said Democratic Sen. Dick Durbin of Illinois in April about the President, the White House deputy chief of staff, and FBI director, further accusing the government of using Section 702 “as a back door for warrantless spying on Americans here at home.” 

Democratic Sen. Ron Wyden of Oregon stated in a “Dear Colleague” letter also from April that Section 702 “must be reformed to better protect Americans’ Constitutional rights and include new safeguards against abuse before it is renewed.”

“At a time when our democracy is under tremendous threat, we owe it to our constituents to have a real, open debate about surveillance authorities that directly affect both their security and their fundamental freedoms,” he wrote. “And we should not exclude Americans from that debate.”

Proponents of an extension are pushing it “based on this specter that Section 702 will go dark,” Elizabeth Goitein, an expert on national security and a senior director at the Brennan Center, tells TIME, noting “the law is clear that the certifications remain in effect even if the underlying statute lapses,” which, she contends, gives ample time to implement reforms that prevent the government from accessing Americans’ data without warrants.

“No government official should have warrantless access to Americans' private communications,” she argues. “The potential for abuse is simply too great.”

-Philip Wang contributed reporting.