Three years ago, Texas lawmakers passed a landmark law that would let state police arrest people suspected of having entered the country illegally by crossing the border.
Such authority has long been the sole responsibility of the federal government, but the state’s Republican leaders said Texas, which shares about 1,250 miles of border with Mexico, had a constitutional right to protect its sovereignty as the number of illegal border crossings hit record highs under the Biden administration.
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But when a federal appeals court rehears oral arguments Thursday in a legal challenge seeking to stop Texas’ law from going into effect, the circumstances outside the courtroom will be much different.
The number of people crossing the border has dwindled to a trickle during President Donald Trump’s first year back in the White House, setting record lows in a sharp reversal from the influx that inspired Texas’ law, known as Senate Bill 4. The new reality on the ground could complicate Texas’ legal argument that it has a constitutional right to defend itself against an invasion, like the one state lawmakers claimed was afoot when they enacted the law. The case carries high stakes for the future of immigration enforcement and the role states are allowed to play.
For Texas, a court ruling in either direction could present a victory. If the Fifth U.S. Circuit Court of Appeals, after hearing Thursday’s arguments, removes the injunction that has blocked SB 4 from taking effect, the state would further solidify its already outsized role in immigration enforcement. If the court keeps the injunction in place, Texas authorities would still be poised to continue the starring and unprecedented role they have played in aiding the Trump administration’s immigration crackdown, even with SB 4 off the books. And state GOP leaders would almost certainly appeal to the U.S. Supreme Court, giving them a possible forum to reconfigure legal precedent that largely prevents states from enforcing immigration law.
“What is at stake most importantly is the ability of migrants to live and feel safe in a state where they have contributed deeply,” said Denise Gilman, a law professor who co-directs the Immigration Clinic at the University of Texas at Austin. “It really could be a watershed moment for how we think about immigration and noncitizens in general in Texas.”
Legal experts say the most pertinent development that could affect the case is the defection of the U.S. Department of Justice, which filed the lawsuit to block SB 4 under the Biden administration before dropping its challenge last year after Trump took office.
SB 4 would make it a state misdemeanor to illegally cross the border and authorize Texas officers to arrest undocumented immigrants. It would also require state magistrate judges to order people arrested for illegal entry — a new state charge created by SB 4 — to leave the U.S. for Mexico in lieu of prosecution, or if they are convicted.
The Biden administration swiftly moved to block the law, arguing in a suit filed weeks after SB 4’s passage that the measure was unconstitutional because the policing of immigration — including oversight of who is allowed into the country and the removal of people without proper documentation — rests in the federal government’s hands alone.
The legal challenge has continued through a case brought by a group of civil rights organizations and El Paso County. Last summer, a three-judge panel from the Fifth Circuit upheld an injunction blocking SB 4, reinforcing a lower court’s finding that the federal government is the main enforcer of immigration law.
The state of Texas appealed, asking to have the case reheard by the entire circuit court, which made the rare move of granting the request. The conservative circuit court — which hears appeals from Texas, Louisiana and Mississippi — has 17 judges, 12 of whom were appointed by Republican presidents, including six by Trump.
Legal experts said the federal government’s switch presents a key question for the court: Do the remaining parties have a legal right — or “standing” — to challenge the law before it has gone into effect, now that the federal government is no longer claiming a conflict?
Texas has argued that the plaintiffs do not have standing because the law has never taken effect, offering no chance for anyone to be affected by it. The state also argues that it has a right to defend its sovereignty because the record migration under Biden amounted to an invasion — a novel legal argument that courts have historically rejected or refused to wade into.
“This law is critical for defending Texas’ fundamental right to protect Texans against illegal immigration,” Attorney General Ken Paxton said in a statement. “My office looks forward to aggressively defending Senate Bill 4 to uphold public safety and address the important standing and preemption principles involved.”
El Paso County officials estimate that SB 4 would result in 8,000 more arrests each year, which they say would strain local jails and courts, and without funding from the state to cover the costs.
“Once again, El Paso was forced to figure out how to pay an unfunded mandate that would not only undermine the County’s financial stability but undermine the trust that local law enforcement has developed with community members,” El Paso County Attorney Christina Sanchez said in a statement to The Texas Tribune.
Immigration enforcement in Texas
In December 2023, the month lawmakers passed SB 4, U.S. Border Patrol recorded nearly 250,000 encounters with migrants along the country’s southwest border.
Since Trump returned to the White House, illegal border crossings have plummeted.
Border Patrol agents working in Texas — home to five of the agency’s nine sectors along the border — recorded just 4,265 migrant apprehensions in December, the most recent month for which federal statistics are available.
In response to the Trump administration and the quiet border, the state has redirected law enforcement previously stationed at the border to helping the federal government with its deportation crackdown across the state.
Texas Department of Public Safety officers have helped arrest thousands of undocumented immigrants for deportation. More than 200 law enforcement agencies across the state have entered agreements with U.S. Immigration and Customs Enforcement that grant local officers limited immigration authority. Texas accounts for roughly one-fifth of all agreements that ICE has inked with local law enforcement agencies, second most behind Florida.
Should SB 4 go into effect, that role would be further expanded with a green light to handle deportations without needing signoff from the feds.
“At the end of the day, the Legislature wrote SB 4 for a specific purpose,” said Jorge Dominguez, of Las Americas Immigrant Advocacy Center, one of the plaintiffs in the lawsuit challenging it. “Even though Texas has more involvement with the federal government in terms of enforcement in the interior, I don’t think that will supplant what the state wants to do with SB 4.”
To immigration hardliners, that is exactly why SB 4 remains important.
Ammon Blair, a former Border Patrol agent who is currently a research fellow at the conservative Texas Public Policy Foundation, contended that fluctuations in the White House’s border enforcement policies — which have contributed to the drop-off in crossings — do not invalidate states’ constitutional right to defend themselves.
While SB 4 would leave Texas well-positioned to act should border crossings increase in the future, Blair said, it would also give state authorities more latitude to help the Trump administration in the meantime.
“In order for the Trump administration to do all the mass deportation efforts they are currently striving for,” Blair said, “the only possible way to do that is by working with local law enforcement.”
Disclosure: Texas Public Policy Foundation and University of Texas at Austin have been financial supporters of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune’s journalism. Find a complete list of them here.