Texas’ immigration law known as Senate Bill 4 is facing a new legal challenge after civil rights organizations filed a lawsuit on Monday seeking to block parts of the measure ahead of its scheduled start date. The plaintiffs asked the court to stop provisions they say would allow Texas police to arrest people suspected of illegally entering the U.S. from Mexico and to give state courts authority to move those cases through removal proceedings.
The new lawsuit was filed by the Texas Civil Rights Project, the American Civil Liberties Union of Texas and the ACLU, according to the complaint described in a report released Monday. It comes after a federal appeals court lifted an injunction that had kept SB 4 paused for years, leaving the law able to take effect unless another court halts it.
SB 4, as described by the plaintiffs and in the report, created a state-level crime tied to entering the country without authorization and also established pathways for state authorities to remove people if convicted. The groups argued that the law intrudes into an area courts have long treated as exclusively belonging to the federal government, and that federal immigration law should preempt Texas’ state approach.
In the lawsuit, the groups focused on four specific provisions they said should be blocked. They sought to challenge the creation of a crime related to re-entering the country without authorization even after a person has obtained legal status, and they challenged provisions that would grant state magistrates authority to order a person’s deportation.
The complaint also targeted what the report described as a crime for failing to comply with a magistrate’s order, and it challenged a requirement that magistrates continue a prosecution even when a person has a pending immigration case such as an asylum claim. The lawsuit thus attempts to halt not only enforcement at arrest and charging, but also the ongoing role Texas officials would play while federal immigration proceedings are pending.
Texas Civil Rights Project executive Kate Gibson Kumar said in a statement that the groups’ fight against SB 4 is not over “until justice wins.” She called SB 4 “unconstitutional” and said it is “a vile law that uses our Texas resources to harm communities across our state.”
The report said Attorney General Ken Paxton’s office did not immediately respond to a request for comment. The lawsuit also described SB 4 as the product of 2023 legislation that Texas Republicans passed after record border crossings, which they framed as an invasion.
A prior legal challenge began in 2024, when the Biden administration was among the plaintiffs. The report said the Trump administration later terminated the Department of Justice’s participation in that case amid the president’s immigration crackdown, and that the litigation continued until two weeks ago when a federal appeals court lifted the injunction for lack of standing by the plaintiffs.
Under the current timeline described in Monday’s report, SB 4 can go into effect May 15 unless it is halted by another court ruling.