The ACLU is sending in the lawyers who stopped Trump’s executive order to argue the constitutionality of Texas’ “sanctuary cities” ban.

On a cold January evening, Lee Gelernt emerged to a cheering crowd outside a Brooklyn courthouse after winning the first legal challenge against Trump’s travel ban. Now, the New York City-based civil rights attorney finds himself deployed to Texas.

To tackle Senate Bill 4 — the “sanctuary cities” ban that critics say will encourage racial profiling and tear immigrant families apart — the American Civil Liberties Union (ACLU) is sending Gelernt and four other attorneys who successfully fought the travel ban to the Lone Star State.

“SB 4 and the travel ban cases raise different technical legal issues, but both arise in, and are part of, an unfortunate anti-immigrant climate,” Gelernt told the Observer. “Both laws rest on incorrect and pernicious stereotypes.”

Gelernt said the ACLU is devoting national resources to fighting the state law “because of the national importance, given that states around the country are talking about similar laws.”

The state of Texas is facing at least three lawsuits over SB 4, which is set to go into effect September 1. The law will allow police to question the immigration status of anyone being detained — not just arrested — and threatens to jail elected officials who limit cooperation with federal immigration agents.

On Monday, the ACLU filed the first motion for an injunction of SB 4 in an attempt to stop the law from going into effect as the battle over its constitutionality plays out. All three suits claim the law violates the constitutional rights of immigrants and Latinos, as well as elected officials who want to protect those groups.

“We have always defended the constitutional rights of immigrants,” said Edgar Saldivar, an attorney with the ACLU of Texas. “We believe SB 4 is unconstitutional for various reasons … and we hope that parts, if not all of it, will be stopped before September 1.”

The ACLU joined the legal battle against SB 4 in late May, becoming co-counsel on a lawsuit brought by the tiny border town of El Cenizo. The city of San Antonio and El Paso County have also filed suits, with counsel from other civil rights organizations. The city of Austin has joined the San Antonio suit.

Texas Attorney General Ken Paxton filed his own pre-emptive lawsuit in May in an attempt to have the law declared constitutional — a move that the Mexican American Legal Defense and Education Fund called “frivolous.”

A spokesperson for Paxton told the Observer the agency “does not comment on ongoing litigation.”

A key argument against Trump’s travel ban, which has been struck down by two appeals courts and now likely heads to the Supreme Court, could also be applied to SB 4. Judges have repeatedly held that Trump’s campaign remarks about Muslims reveal the ban’s discriminatory intent.

Victory: ACLU Attorney Lee Gelernt WATCH: Deputy Legal Director of the Immigrants Rights Project Lee Gelernt coming out of the court where the ACLU argued to block Trump's unconstitutional Muslim ban. "The judge saw through what the government was doing and gave us what we wanted which was to block the Trump order." Posted by ACLU Nationwide on Saturday, January 28, 2017

Attorney Jose Garza, with the El Paso lawsuit, said he plans to use Representative Matt Rinaldi’s decision to report protesters at the Capitol to immigration agents to show discriminatory intent in court.

For now, though, the ACLU hasn’t included that argument in the El Cenizo suit.

“Our current motion does not hinge on statements made by legislators, but that could come later,” Gelernt said. “We think that SB 4 is unconstitutional regardless of the intent behind the law.”