Civil Rights Groups Sue to Block Texas Law Authorizing Police to Arrest Undocumented Migrants

On May 4, 2026, a coalition of civil rights organizations filed a federal lawsuit seeking to block Texas Senate Bill 4 days before it takes effect, setting up what may become the most consequential federalism fight over immigration enforcement since Arizona's SB 1070 reached the Supreme Court in 2012 [1][2].

The law, passed by the Texas Legislature in 2023 but tangled in courts ever since, creates state-level criminal offenses for entering Texas from Mexico without authorization and empowers local police to arrest individuals suspected of illegal entry. After the conservative Fifth Circuit Court of Appeals ruled in April 2026 that the original challengers lacked standing — sidestepping the constitutional merits entirely — the law is now cleared to take effect on May 15 [3][4].

What the Law Does

SB 4 contains four principal provisions [1][5]:

1. A new state crime for illegal entry. It criminalizes entering Texas from a foreign country other than through a lawful port of entry — a Class B misdemeanor for a first offense, elevated to a second-degree felony for those previously deported or subject to removal orders.

2. State-ordered deportation. It authorizes Texas magistrate judges to order individuals convicted under the law to return to Mexico, creating a parallel state deportation mechanism.

3. Criminal penalty for noncompliance. Failure to comply with a magistrate's removal order is itself a separate offense.

4. Prosecution regardless of pending federal cases. It requires magistrates to continue prosecutions even when defendants have pending asylum claims or other federal immigration proceedings.

The Congressional Research Service noted that SB 4 "intrudes on the federal government's exclusive authority over the admission and removal of aliens" and "conflicts with federal statutes allowing certain aliens who unlawfully entered the United States to obtain relief from removal" [5].

The Supremacy Clause Problem: Arizona's Precedent

The constitutional question is not new. In Arizona v. United States (2012), the Supreme Court struck down three of four challenged provisions of Arizona's SB 1070, holding that federal immigration law preempted state enforcement schemes [6]. Justice Kennedy's majority opinion established that "the Federal Government has occupied the field of alien registration" and that states cannot impose criminal penalties in an area Congress has comprehensively regulated.

The sole surviving provision — Section 2(B), which required officers to check immigration status during lawful stops if they had "reasonable suspicion" — was upheld only under a narrow reading: officers could not extend detentions solely for immigration verification, and the provision remained subject to future racial profiling challenges [6][7].

Texas's SB 4 goes substantially further than Arizona's surviving provision. Rather than merely requiring status checks during otherwise lawful stops, it creates entirely new criminal offenses and a state-run removal system — exactly the kind of parallel enforcement architecture the Court struck down in 2012.

Who Filed Suit, and On What Grounds

The new lawsuit was brought by the ACLU of Texas, the Texas Civil Rights Project, and the national ACLU on behalf of Las Americas Immigrant Advocacy Center, American Gateways, and individual plaintiffs including a lawful permanent resident and a U Visa holder [1][8].

Their constitutional claims include:

• Supremacy Clause preemption: Immigration enforcement is exclusively federal, and SB 4 conflicts with the Immigration and Nationality Act.
• Fourth Amendment: Every arrest under SB 4 constitutes an unconstitutional seizure because probable cause for the state crime depends on immigration status determinations that state officers cannot lawfully make.
• Eighth Amendment: State-imposed banishment (the magistrate removal orders) constitutes cruel and unusual punishment.
• Fourteenth Amendment due process: The law strips defendants of the right to pursue federal immigration relief such as asylum.

"Our fight against SB 4 isn't over until justice wins," said Kate Gibson Kumar of the Texas Civil Rights Project. "SB 4 is not only unconstitutional, but a vile law that uses our Texas resources to harm communities across our state" [1].

The plaintiffs are seeking a preliminary injunction before the May 15 effective date. Based on the trajectory of prior challenges — the original SB 4 case received an injunction from Judge David Ezra within weeks of filing in early 2024 — emergency relief could come quickly, though the Fifth Circuit's April standing ruling complicates the picture [3][4].

The Case for the Law

Governor Greg Abbott and supporters argue SB 4 fills a measurable gap in federal enforcement. Abbott, alongside Hidalgo County Sheriff Eddie Guerra and McAllen Police Chief Victor Rodriguez, published an op-ed defending the law as necessary to "identify dangerous criminals" and arguing it includes "new protections for crime victims and witnesses" while explicitly "prohibiting racial profiling and discrimination" [9][10].

Twenty-three additional law enforcement officials signed on to support the governor's position [10].

Proponents cite specific data points: CBP apprehension data for March 2026 showed a 25% decline, which supporters attribute partly to the deterrent effect of state-level criminal exposure [9]. The Texas 2026 budget allocated $500 million for immigration enforcement partnerships and trained 2,500 local officers under the federal 287(g) program [9].

The core policy argument is that federal detainer non-compliance by certain local jurisdictions has allowed individuals with deportation orders to remain in communities. Supporters contend that when the federal government declines to enforce its own removal orders, the state has a sovereign interest in public safety that justifies filling the vacuum — even if it means testing the boundaries of Arizona v. United States.

Attorney General Ken Paxton's office has characterized the Fifth Circuit's April ruling as a vindication, though it did not address the merits of the preemption argument [4].

Who Lives Under This Law: The Population at Risk

An estimated 2.1 million undocumented immigrants live in Texas as of 2024, representing approximately 7% of the state's total population [11][12].

Source: Migration Policy Institute

Data as of Jan 1, 2025CSV

The demographic reach extends far beyond those 2.1 million. According to the Migration Policy Institute and FWD.us [11][13]:

• 1.1 million U.S.-born children have at least one undocumented parent in Texas — roughly 16% of all children in the state.
• 713,000 U.S. citizen children live directly with an undocumented parent.
• 191,000 U.S. citizen spouses are married to an undocumented immigrant.
• 315,000 children under 18 are themselves unauthorized.

Beyond mixed-status families, additional groups face exposure:

• DACA recipients: Texas has one of the largest DACA populations nationally. At least 75 DACA recipients were arrested in Texas between January and November 2025, and between 86 and 174 have been deported nationwide according to conflicting DHS figures [14].
• Asylum seekers with pending cases: Individuals who crossed between ports of entry to file asylum claims — a practice recognized under federal law — could be arrested under SB 4 even while their cases are pending.
• Legal permanent residents: One named plaintiff in the new lawsuit is a lawful permanent resident who fears being subjected to stops and arrests based on appearance [8].

The law's criminal provisions target crossing "between ports of entry," which means enforcement would concentrate along the 1,254-mile Texas-Mexico border. Mexico remains the origin country for 50% of Texas's undocumented population (1.05 million), with Central American nations contributing another 25% [11].

Implementation Realities: Police, Jails, and Cost

The operational questions are significant. When the Texas Senate considered SB 4, eight witnesses testified in support while more than 1,600 opposed it. The police chiefs of six Texas cities and the executive director of the Texas Police Chiefs Association publicly opposed the bill, calling it "political pandering that will make our communities more dangerous" [10][15].

Their objections centered on practical concerns:

• Training: Texas has not provided official training, funding, or guidance on implementation. Officers would need instruction on probable cause standards for immigration-related arrests — a domain with specialized legal doctrines unfamiliar to most local police [10].
• Community trust: Police chiefs in majority-Latino cities argue that immigration enforcement authority will deter crime reporting by immigrant communities, making everyone less safe [15].
• Detention capacity: Culberson County Sheriff Oscar Carillo stated his jail is already at capacity, and housing immigration detainees "would require discussion with his county attorney" [10]. Border counties with small budgets face the most pressure.

The fiscal burden could be substantial. ICE detention currently costs an average of $152–165 per person per day, and individuals spend an average of 44 days detained [16][17].

Source: National Immigration Forum / DHS

Data as of Sep 1, 2025CSV

If Texas counties must house immigration arrestees pending federal processing — and SB 4 provides no state funding mechanism for local detention — border counties could face costs of $6,600–7,260 per detainee for a single 44-day hold. For a county like Culberson (population ~2,200) or Hudspeth (population ~4,800), even a handful of prolonged detentions could strain budgets already operating at the margin.

The national ICE detention population reached a record of approximately 73,000 in early 2026, far exceeding the system's funded capacity of roughly 41,500 beds [16]. Texas facilities are already operating at or near capacity — the El Paso Camp East Montana facility alone averaged 2,505 detainees per day in FY2026 [16].

Arizona's Warning: What Happened Under SB 1070

Arizona's experience provides a partial roadmap for projecting outcomes in Texas. After SB 1070 passed in 2010, the ACLU documented that Latino drivers were 4.6 times more likely than non-Latino drivers to be stopped and questioned by law enforcement [7][18].

Section 2(B)'s "show me your papers" requirement — the only provision to survive Supreme Court review — was in effect for periods between 2010 and 2016 before enforcement guidance from Arizona's attorney general narrowed its application. During that period [7][18]:

• Multiple federal civil rights investigations were opened into Arizona law enforcement agencies.
• Maricopa County Sheriff Joe Arpaio's office was found by the DOJ to have engaged in a pattern of racial profiling, leading to a federal consent decree.
• Research from Georgetown University Law Center concluded that SB 1070 created "pervasive" racial profiling against Latinos and Asian Americans "presumed to be illegal immigrants solely based on their appearances."
• The law prompted significant population outflows of Latino residents — including U.S. citizens — from Arizona before courts intervened.

Texas's law grants broader arrest authority than Arizona's surviving provision, raising the question of whether enforcement patterns would be amplified.

The Legal Road Ahead

The new lawsuit faces a complicated procedural landscape. The Fifth Circuit's April 2026 standing ruling — which dismissed the prior challenge on procedural grounds without reaching the constitutional merits — does not bind this new case, which features different plaintiffs with different claims of injury [3][4].

The plaintiffs have filed in the Western District of Texas, where Judge Ezra previously granted an injunction in the earlier case. If the court follows its own prior reasoning, a temporary restraining order could issue before the May 15 effective date.

However, any injunction would almost certainly face immediate appeal to the Fifth Circuit, which has shown sympathy to Texas's position on procedural grounds. The ultimate resolution likely requires the Supreme Court to decide whether SB 4's provisions are materially distinguishable from the Arizona statutes it struck down in 2012 — or whether the current Court, with a 6-3 conservative majority, is prepared to revisit that precedent entirely.

For the 2.1 million undocumented Texans, 1.1 million U.S. citizen children in mixed-status families, and the local police departments caught between state mandates and community relationships, the answer matters immediately.

Texas Attorney General Ken Paxton's office did not respond to requests for comment regarding the new lawsuit [1].