Attorney General Jeff Sessions has launched a new offensive in his longstanding war with so-called “sanctuary” policies that shield undocumented immigrants.

The Department of Justice sued California on Tuesday, claiming three state laws unconstitutionally interfere with efforts to strictly enforce federal immigration law. Sessions is scheduled to speak to state law enforcement officials Wednesday morning in Sacramento, and he is expected to elaborate on his rationale for filing the lawsuit. Sanctuary policies allow states and cities to shield undocumented immigrants in various ways to block the Trump administration’s campaign to detain and deport as many of them as possible.

"The Department of Justice and the Trump administration are going to fight these unjust, unfair, and unconstitutional policies that are imposed on you," Sessions plans to say, according to excerpts of his remarks released by the DOJ. "We are fighting to make your jobs safer and to help you reduce crime in America. And I believe that we are going to win."

So far, coverage of the lawsuit has mostly focused on one specific sanctuary policy, California law SB54, which took effect this year. Under the law, local cops are prohibited from alerting immigration agents when people are about to be released from custody for low-level offenses. The feds want advance notice so that people who are wanted for immigration violations can be re-arrested and locked up in detention centers pending deportation. The law also blocks jails from asking inmates about their immigration status, and bans federal immigration agents from accessing local jails.

“These provisions impermissibly prohibit even the most basic cooperation with federal officials,” the Justice Department argues in its lawsuit, claiming the policies create “an obstacle to the United States’ enforcement of the immigration laws.”

But the lawsuit also challenges two other California laws. One is the state’s Immigrant Worker Protection Act, which prohibits businesses from voluntarily providing information to federal immigration agents about employees. It also requires employers to let workers know if the feds are going to inspect their records.

The third law that’s under fire requires state inspections of federal immigrant detention centers. State lawmakers enacted the measure in response to reports of poor conditions and detainee abuse in the facilities, many of which are operated by private prison companies. As the Justice Department’s lawsuit notes, the law also requires California’s attorney general to ensure that due process is being provided to civil immigration detainees, and investigate “the circumstances around their apprehension and transfer” to federal detention facilities.

Sessions maintains that everything about the facilities should be kept secret — unless the federal government decides the information should be released to the public. The lawsuit also claims the state “has no lawful interest in investigating federal law enforcement efforts.”

A senior Justice Department official told the Washington Post that other states and cities with sanctuary laws could face separate lawsuits, but California will offer a high-profile test case that may determine whether the administration’s legal challenge has merit. The Center for Immigration Studies, which supports restrictions on immigration, counts six sanctuary states and dozens of counties with similar policies.

So far, efforts by Sessions to force states and cities to help enforce federal immigration laws have hit a wall in federal court. Judges in San Francisco and elsewhere have summarily rejected the Trump administration’s attempts to withdraw federal funding from sanctuary jurisdictions.

California Atty. Gen. Xavier Becerra said the state is ready to fight. "We are doing what we believe is best to make sure the people of California are safe," he said, according to the Los Angeles Times. "We are doing nothing to intrude on the work of federal government to do immigration enforcement."