One hundred and sixty members of Congress on Friday urged the U.S. Supreme Court to block the Trump administration from ending an Obama-era policy that postponed deportation for about 800,000 young immigrants illegally brought into the country as children.

Ahead of oral arguments next month, the amicus brief — signed by all 45 Senate Democrats and 115 House Democrats along with a dozen former lawmakers, including four Republicans — asserts that the Trump administration was wrong when it moved in 2017 to end Deferred Action for Childhood Arrivals on the grounds that it exceeded executive authority.

“Congress has long recognized that the executive branch must have discretion to determine how best to enforce the nation’s immigration laws,” the legislators said. “The government cannot possibly remove everyone who is eligible for removal. Accordingly, the executive branch necessarily must exercise substantial discretion in determining who should be removed.”

While the government last month offered other reasons it wanted to end DACA, including a concern that it encouraged adult migrants to bring children on the perilous journey to the United States, the lawmakers contended that “what matters is the explanation the executive branch offered at the time it terminated DACA — namely, that it had concluded that DACA was unlawful.”

Sen. Dick Durbin, D-Ill., in a press release, touted the amicus brief as bipartisan despite the absence of any currently serving Republicans.

The four former GOP representatives who signed on are Ray LaHood of Illinois, who led the U.S. Department of Transportation in the Obama administration; Constance Morella, a moderate Marylander who lost her seat in 2002 to now-Sen. Chris Van Hollen, D-Md.; Claudine Schneider of Rhode Island, a liberal Republican and environmental advocate who left Congress in 1991; and one-term Vermont centrist Peter Smith, who lost his seat to now-Sen. Bernie Sanders, I-Vt., in 1990.

The case has drawn a flurry of amicus filings.

On Thursday and Friday, the court posted 15 briefs from DACA supporters including the Mexican government, prosecutors and law enforcement leaders who say the program promotes community cooperation.

One of the supportive filings came from former leaders of the U.S. Department of Homeland Security, U.S. Citizenship and Immigration Services and U.S. Customs and Border Protection. The former officials, almost all veterans of the Obama administration, defended the choice to defer deportation and give work permission as rooted in historical practice.

More than 140 companies and business groups that say they don’t want to lose their protected employees, major labor unions that said beneficiaries contribute to unions and the overall economy, and 165 colleges and universities that say recipients contribute to their campuses, also wrote in support of DACA.

Previous amici in favor of DACA include the attorneys general of 17 Democrat-led states, Apple Inc. CEO Tim Cook and the Mexican American Legal Defense and Educational Fund. Opponents include 13 attorneys general from GOP-led states, the libertarian-leaning Cato Institute think tank and two groups that advocate for American tech workers.

Implemented by President Barack Obama through executive action in 2012, DACA has offered deportation protection and work authorization to young immigrants who came to the U.S. without authorization as children.

In moving to rescind the act in September 2017, the Trump administration said Obama’s creation of the program constituted an unlawful overreach of his executive authority. The government claimed the program suffered from the same legal deficiencies as Obama’s Deferred Action for Parents of Americans program, which a Texas federal court struck down in a February 2015 ruling later affirmed by the Fifth Circuit.

The U.S. Department of Justice declined to comment. Spokespeople for Republican congressional leaders did not immediately respond to requests for comment Friday.

The lawmakers on the amicus brief are represented by Brianne J. Gorod, Elizabeth B. Wydra, Brian R. Frazelle and Dayna J. Zolle of the Constitutional Accountability Center.

The government is represented by U.S. Solicitor General Noel J. Francisco.

The consolidated cases are DHS et al. v. Regents of the University of California et al., Trump et al. v. NAACP et al., and Acting DHS Secretary Kevin K. McAleenan et al. v. Martin Jonathan Batalla Vidal et al., case numbers 18-587, 18-588 and 18-589, before the Supreme Court of the United States.