Private-prison companies that allegedly force undocumented immigrant detainees to work for little or no money have a powerful new group of advocates: Eighteen members of Congress.

The members, all Republicans, sent a letter to Attorney General Jeff Sessions, the head of Immigration and Customs Enforcement (ICE), and the Department of Labor, calling for them to help private-prison company GEO Group defend itself in lawsuits by former detainees.

Over the last few years, immigrants’ rights activists have filed a number of lawsuits against private prison companies related to immigrant work programs. The lawsuits argue that these companies, including GEO Group and CoreCivic, break a law against human trafficking by having detainees work for a $1 per day or less.

GEO Group filed the congressmen’s letter with U.S. District Court in the Central District of California on March 12 as part of the Novoa v. GEO Group suit. It argues that immigrants should not be able to sue prison companies because they aren’t employees there, and that paying them $1 per day for their work is lawful. The letter also said that the allegedly forced labor saves the government money and improves detainees’ morale.

Congressmen wrote that the work program’s purpose is to “(1) enhance detention operations and services through detainee productivity; and to (2) reduce the negative impact of confinement through decreased idleness, improved morale, and fewer disciplinary incidents.”

“Unless your agencies act to intervene in these lawsuits, immigration enforcement efforts will be thwarted,” the letter reads.

The letter was signed by Lamar Smith, Jody Hice, Matt Gaetz, Steve King, Mike Rogers, Paul Gosar, Andy Biggs, Louie Gohmert, Dana Rohrabacher, Paul Cook, Scott Taylor, Earl “Buddy” Carter, John Ratcliffe, Duncan Hunter, Bob Gibbs, Barry Loudermilk, Brian Babin, and John Rutherford.

In a statement provided to The Daily Beast, GEO spokesperson Pablo Paez noted that the company's labor practices have been in place for years, including under the Obama administration.

“The Obama Administration set the Performance-Based National Detention Standards which govern the Voluntary Work Program at all ICE Processing Centers, public and private,” Paez said. “The wage rates associated with this federally mandated program are stipulated under long-established guidelines set by the United States Congress. As a service provider to the federal government, GEO is required to abide by these federally mandated standards and congressionally established guidelines. GEO has consistently, strongly refuted the allegations made in these lawsuits, and we intend to vigorously defend our company against these baseless claims.”

GEO Group and CoreCivic, the nation’s two largest private prison companies, have contributed to six of those members’ campaigns: Gaetz, Rutherford, Cook, Taylor, and Ratcliffe. In total, they have given those six members just over $20,000 since 2015.

Editor’s note: This story has been updated with comment from GEO Group and to highlight the fact that they dispute the allegations of forced labor.