The U.S. House of Representatives could soon vote to do something truly historic and deeply dangerous: authorize the warrantless surveillance of Americans. That’s unless Democratic leaders — starting with House Minority Leader Nancy Pelosi — speak out.

The bill in question, unveiled last Friday, would reauthorize a section of the Foreign Intelligence Surveillance Act. This powerful law allows the National Security Agency to collect emails and phone calls without a warrant or evidence of wrongdoing, but only if the target of surveillance is a foreigner overseas.

The problem arises because this surveillance inevitably sweeps in enormous amounts of Americans’ communications. The law requires the government to “minimize” the retention and sharing of such “incidentally” acquired data. Instead, as Edward Snowden’s disclosures revealed, the CIA, FBI and NSA routinely search their collections for Americans’ phone calls and emails — a practice known as “backdoor searches.”

A law designed to target foreign threats has thus become a rich source of warrantless access to Americans’ data. The potential for abuse is evident under any administration. For instance, FBI officials could search for communications of Black Lives Matter activists known to have foreign relatives in order to keep tabs on their activities. The risk of misuse is particularly worrisome under President Trump, who flaunts his grudges against political adversaries and has pledged to intensify mosque surveillance.

There is striking bipartisan consensus that this section of the law must be revised to better protect Americans’ privacy. Lawmakers hailing from the progressive left to the Tea Party right have introduced bills requiring the government to obtain a warrant before attempting to access Americans’ communications. Even California Democratic Sen. Dianne Feinstein, a former intelligence committee chair who generally favors broad surveillance powers, supports a warrant requirement.

Republican leadership, however, has backed a series of bills that masquerade as reform while authorizing warrantless searches. Just before the holiday recess, House Speaker Paul Ryan scheduled a vote on a bill that gave the government the option of applying for a warrant. This putative “reform” did not pass the laugh test, and Ryan was quickly forced to cancel the vote.

The most recent bill is cut from the same cloth. It would require a warrant to access Americans’ communications, but only in “predicated” criminal investigations unrelated to national security or foreign intelligence.

The exceptions in the bill would devour the rule. The government has adopted extremely broad definitions of “national security” and “foreign intelligence.” Almost any investigation of an immigrant or a Muslim American could be shoehorned into those definitions, and there would be no way to challenge the designation.

Even without those exceptions, the bill’s warrant requirement is largely meaningless because it applies only to “predicated” criminal investigations — namely, later-stage investigations based (or “predicated”) on well-developed facts. Perversely, the government would remain free to conduct warrantless searches during the earlier, “assessment” phase of the investigation, when there is less evidence of wrongdoing.

This back-loaded approach would do more harm than good. Because warrantless searches could occur only in the early stages, FBI agents would have an incentive to conduct them the moment they received the barest tip, however unsupported or unreliable.

Moreover, for early-stage investigations and those deemed to have “national security” or “foreign intelligence” components, the bill expressly authorizes warrantless access to Americans’ communications. It thus codifies a practice not authorized in current law, effectively overriding the requirement to minimize the use of this incidentally collected data.

Rep. Jerrold Nadler, D-N.Y., ranking member of the House Committee on the Judiciary, aptly describes the bill as “written by the intelligence community, for the intelligence community.” Unfortunately, few outside the FBI know what a “predicated” investigation is. Ryan is banking on this fact, hoping to sell the bill as a pro-privacy measure.

The gambit could succeed. Pelosi and other Democratic Party leaders have remained conspicuously silent on the faux-reform bills, even as Republicans such as Ted Poe of Texas have denounced them. They may not see the flaws beneath the window dressing. Or they may be reluctant to enter the fray for fear of seeming soft on national security.

Whatever the cause, their reticence is endangering their constituents’ rights. Congress passed this law to enable detection of foreign threats, not warrantless surveillance of Americans. Backdoor searches violate the law’s premise and Americans’ privacy. And they don’t make us safer: The government has never even claimed that backdoor searches have helped to thwart terrorist plots.

Pelosi’s influence over her caucus is legendary. It’s down to her and her leadership team to line up Democrats behind real reform. If they don’t, the Trump administration may soon be able to add another legislative victory to December’s tax bill: Congress’s blessing for warrantless domestic spying.

Elizabeth Goitein is co-director of the Liberty & National Security Program at the Brennan Center for Justice at NYU School of Law.