A federal appellate panel said on Friday that Iowa could not enforce a Republican-backed law that made it a state crime for some undocumented immigrants to enter the state. The ruling keeps in place a lower court’s injunction that blocks, at least for now, Iowa’s attempt to change how immigration crimes are policed in the United States.
The fight in Iowa comes as part of a broader effort by conservative states to carve out a role in immigration enforcement by creating their own laws. In doing so, they entered legal territory that former President Joseph R. Biden Jr.’s Justice Department argued should be the exclusive domain of federal officials.
President Trump is taking a much harsher approach to illegal immigration in his second term, and has promised mass deportations. But it was not yet clear how his Justice Department would approach cases like the one in Iowa. Justice Department officials did not immediately respond to a request for comment on Friday.
The Iowa attorney general’s office said it was evaluating its next steps in the case. Attorney General Brenna Bird, a Republican, said in a statement that “despite today’s court ruling, the battle is far from over.”
“As President Trump works nationally to fix the mess Biden and Harris created on the southern border,” Ms. Bird added, “we will continue fighting in Iowa to defend our laws and keep families safe.”
The three-judge panel of the U.S. Court of Appeals for the Eighth Circuit that heard the Iowa case was composed entirely of jurists appointed by Republican presidents. It included one judge appointed by Mr. Trump, one by former President George W. Bush and one by former President George H.W. Bush.
“The United States details several ways the act may interfere with the enforcement of federal immigration law,” Judge Duane Benton wrote in the opinion, which did not note any dissents.
Judge Benton wrote that allowing the law to take effect could incentivize immigrants “to move from Iowa to different states, forcing federal officials to expend limited resources to locate them” and “may antagonize foreign nations whose citizens are affected.”
The ruling was celebrated by immigrant rights groups during a week in which the new president has moved to crack down on illegal immigration.
“This decision affirms what courts around the country have made clear: States have no business regulating immigration, and they cannot take away the rights that immigrants have under federal law, including the right to seek asylum,” Spencer Amdur, an American Civil Liberties Union lawyer, said in a statement.
Their decision may not be the final word. The panel’s preliminary ruling could be appealed, and the case has yet to go to trial on its merits at the district court. The U.S. Supreme Court could ultimately consider the question of whether states can enforce their own immigration laws, in a challenge to either the Iowa law or to similar measures passed in Louisiana, Oklahoma and Texas.
In November, Arizona voters approved a ballot measure that would make it a state crime to enter the state outside official ports of entry or to refuse to comply with orders to leave the United States, though that law would not take effect unless the courts allowed another state to enforce a similar law.
The details of the new laws vary from state to state. Iowa’s measure, passed in 2024 by the Republican-controlled Legislature and signed into law by Gov. Kim Reynolds, does not go as far as some others.
The Iowa legislation makes it a misdemeanor to enter the state if a person was previously deported, denied entry to the United States or left the country while facing a deportation order. In some cases, including if a person had certain prior convictions, the state crime would become a felony. Iowa police officers would not be allowed to make arrests under the legislation at schools, places of worship or health care facilities.
Republican leaders in the state said the measure was necessary because of what they described as a failure by the Biden administration to control the U.S.-Mexico border. A Democratic legislator who opposed the measure called it “a political stunt and a false promise.” But when the legislation passed, Ms. Reynolds, a Republican, said Mr. Biden’s administration had “compromised the sovereignty of our nation and the safety of its people,” which compelled the state to act.
“The United States and Iowa are facing an immigration crisis,” Eric Wessan, Iowa’s solicitor general, told the Eighth Circuit panel in September during oral arguments in St. Louis. “Responding to that unprecedented crisis, Iowa enacted a state crime of illegal re-entry.”
The Justice Department under Mr. Biden said Iowa had no authority to enforce immigration laws itself. Before the law could take effect, the Biden administration convinced a federal district judge in Des Moines to issue a preliminary injunction.
“As a matter of politics, the new legislation might be defensible,” Judge Stephen Locher, a Biden appointee, wrote when he granted the injunction in June. “As a matter of constitutional law, it is not.”
