Civil rights organizations filed a lawsuit Thursday challenging the Trump administration’s policy of requiring asylum seekers to stay in Mexico while their cases play out, saying it “eviscerates” long-standing protections for individuals fleeing persecution.

The lawsuit was filed on yet another bizarre day in D.C.: The White House said that Trump would declare a national emergency to bypass Congress and fund the construction of a 200-mile steel-concrete wall on the southern border, even as he signed a bipartisan spending bill on border security that explicitly does not fund the wall.

But while public attention has focused on the back-and-forth over the wall, the administration’s policy of requiring refugees applying for asylum from Mexico to remain in Mexico while their cases are decided — a process that routinely takes months or years — could have more immediate and far broader consequences.

The lawsuit, filed in federal court in the Northern District of California by the ACLU and the Southern Poverty Law Center, among other civil rights groups, names the Department of Homeland Security, U.S. Citizenship and Immigration Services, U.S. Customs and Border Protection, and U.S. Immigration and Customs Enforcement as defendants. It asks the court to vacate the policy and allow asylum seekers to remain in the U.S.

A representative for Customs and Border Protection said the agency doesn’t comment on pending litigation. ICE referred reporters to the Department of Homeland Security, which didn’t respond to a request for comment.