The ACLU, ACLU of Texas, and the Texas Civil Rights Project filed a class-action lawsuit on May 4, 2026, asking a federal court to block several provisions of Texas Senate Bill 4 from taking effect on May 15, 2026 [1][2]. Plaintiffs seek a temporary restraining order and a preliminary injunction to halt enforcement before the statute's effective date [1].
Texas Senate Bill 4 created a state-level criminal offense for illegal border crossing and established state-administered deportation pathways, placing Texas among the first states to attempt direct enforcement of immigration removal outside the federal system [2]. The lawsuit was filed in federal court under the caption LML v. Martin and names state officials as defendants [1]. The filing follows a federal appeals court decision that lifted an earlier injunction that had previously blocked the law, clearing the path for SB 4 to take effect absent new court action [2].
Immigration enforcement authority under federal law is grounded in the Supremacy Clause and the Immigration and Nationality Act, which courts have long interpreted to preempt state regimes that purport to replicate or supplement federal removal processes [2]. Plaintiffs argue that SB 4 conflicts with that preemption framework, exposing class members to state criminal prosecution and deportation proceedings that only federal authorities are authorized to conduct [1][2]. The request for emergency relief signals that plaintiffs view the May 15 effective date as a hard deadline, leaving the court little time to conduct extended briefing before the law activates [1].
The immediate procedural question is whether the court will grant the temporary restraining order ahead of May 15, which would preserve the status quo while full briefing on the preliminary injunction proceeds [1]. The state is expected to argue that the appeals court's decision to lift the prior injunction forecloses renewed emergency relief on the same legal theory. How the court resolves that threshold question will determine whether SB 4 takes effect on schedule or enters another period of judicial suspension. A ruling against the plaintiffs at the restraining order stage would not foreclose further appellate review, and the litigation is likely to return to the same appeals court that previously lifted the injunction [2].