A federal judge has blocked a key provision of Florida’s 2023 immigration law, championed by Gov. Ron DeSantis, that criminalizes transporting undocumented immigrants, ruling it unconstitutional and beyond state authority.

A federal judge on Wednesday blocked a key part of a 2023 law championed by Gov. Ron DeSantis that aimed to crack down on illegal immigration, finding the law “intrudes upon territory” under the responsibility of the federal government.

The lawsuit, filed in July by The Farmworker Association of Florida, Inc. and individual plaintiffs, centers on part of the law (SB 1718) that threatens felony charges for people who transport an immigrant who “entered the United States in violation of law and has not been inspected by the federal government since his or her unlawful entry.”

The plaintiffs asked U.S. District Judge Roy Altman for a preliminary injunction blocking that part of the law, arguing it is unconstitutionally vague and that the state lacks authority to regulate immigration.

Lawyers for the state urged the judge to reject the request, saying concerns about the law were “misplaced.”

Altman’s preliminary-injunction ruling Wednesday prohibited state and local officials from enforcing a section of the law dealing with transportation of people.

The judge cited previous federal court rulings, including decisions by the Atlanta-based 11th U.S. Circuit Court of Appeals, that he said consistently established that immigration is a matter governed by federal — not state — law. The 11th Circuit hears cases from Florida, Georgia and Alabama.

“By making it a felony to transport into Florida someone who ‘has not been inspected by the federal government since his or her unlawful entry,’ Section 10 (the disputed section of the law) extends beyond the state’s authority to make arrests for violations of federal immigration law and, in so doing, intrudes into territory that’s preempted,” Altman wrote.

Federal appellate courts “have uniformly ruled that ‘prohibitions on the transportation, harboring, and inducement of unlawfully present aliens’ fall into a ‘preempted field,’” Altman’s order said.

Lawyers for Attorney General Ashley Moody’s office argued, in part, that the law is not preempted because it regulates more than transportation of undocumented immigrants. Altman wrote that the state contended the phrase “has not been inspected by the federal government since his or her unlawful entry” could also apply to U.S. citizens returning to the country.

“We’re not persuaded. For one thing, common sense dictates that the category of uninspected citizens —as opposed to uninspected aliens — covers a relatively small (and statistically insignificant) subset of people,” wrote Altman, who was appointed as federal judge in Florida’s Southern District by former President Donald Trump in 2018.

In addition, the U.S. Supreme Court “has made clear” that “even complementary state regulation is impermissible” where Congress “occupies an entire field,” he added.

“It therefore stretches credulity for the defendants to suggest that Section 10 ‘does not directly regulate the transportation of illegal aliens’ and ‘merely overlaps with federal law in some of its applications,’” Altman wrote, quoting the state’s lawyers. “In any event, we’ve found no precedent for the defendants’ view that a party can circumvent field or conflict preemption by marginally expanding a regulation to cover a small, additional category of situations (or people).”

Civil-rights groups that represented the plaintiffs include the American Civil Liberties Union, ACLU of Florida, Americans for Immigrant Justice, the American Immigration Council, and the Southern Poverty Law Center. The plaintiffs’ attorneys praised Altman’s ruling.

“The court was right to block this callous and patently unconstitutional law, which had threatened Floridians with jail time for doing the most ordinary things, like going to work, visiting family, and driving kids to soccer games. This ruling is an important victory for Florida communities,” Spencer Amdur, senior staff attorney with the American Civil Liberty Union’s Immigrants’ Rights Project, said in a prepared statement.

The 2023 law — passed in the run-up to DeSantis’ unsuccessful bid for the Republican presidential nomination — is among a number of steps DeSantis and the GOP-controlled Florida Legislature have taken in recent years targeting undocumented immigrants.

Other parts of the law include stepping up requirements on businesses to check the immigration status of workers and collecting data about whether hospital patients are in the country legally. The measure also steered $12 million to the state Division of Emergency Management for the “Unauthorized Alien Transport” program, which could transport undocumented immigrants to other states. The program would be similar to the DeSantis administration’s controversial flights in 2022 of 49 migrants from Texas to Martha’s Vineyard in Massachusetts.

Those parts of the law were not affected by Altman’s ruling.

In a news release last year announcing he had signed the bill, DeSantis called the package “the most ambitious anti-illegal immigration laws in the country, fighting back against reckless federal government policies and ensuring the Florida taxpayers are not footing the bill for illegal immigration.”

In the motion for a preliminary injunction, the plaintiffs’ attorneys argued that the law “imposes a staggering hardship on plaintiffs, other Floridians and travelers to Florida, who now face criminal penalties for visiting their families, doing their jobs, seeking medical care and engaging in other everyday activities.”

The plaintiffs’ lawyers argued, in part, that the state’s category of “inspected” migrants is not included in a federal law, the Immigration and Nationality Act, and that it was “created out of whole cloth.”

“Because the INA (Immigration and Nationality Act) does not answer whether a person has been ‘inspected’ ‘since’ entry, Section 10 puts state and local officials in the untenable position of determining this classification themselves,” the motion said. “To enforce Section 10, Florida police, prosecutors, judges, and juries would have to examine a passenger’s entire immigration history, and then determine whether that history includes ‘inspection’ ‘since’ entry, without any federal definition to consult. There is no federally issued document that confirms whether a person has been ‘inspected’ since entry. There is no federal official to call, because federal officials cannot determine whether a person meets a classification that does not exist in federal law.