In response, the Trump administration tried to cut off federal funds to punish cities in California for their policies. Last year, a federal judge ruled that strategy unconstitutional.
So late Tuesday, the Trump administration went on the offensive in a dramatic way. The Justice Department sued California, alleging that three new state laws designed to protect certain undocumented immigrants from deportation by the federal government are unconstitutional.
Immigration experts on both sides say this kind of lawsuit takes the sanctuary-cities debate into uncharted territory, and it's not clear what the result will be — other than a likely escalation to the Supreme Court.
“There is real uncertainty about who will win it,” said Ilya Somin, law professor at George Mason University.
That's in part because the legal landscape on federal vs. state rights, especially when it comes to immigration, is a choose-your-own-adventure. Lower courts have split on whether it is legal for the federal government to require local law enforcement to hand over immigrants. There are also intersecting and sometimes contradictory laws about state rights and immigration.
The Justice Department argues that California is violating the Constitution's supremacy clause, which says that federal law is the supreme law of the land. "Federal law determines immigration policy," Attorney General Jeff Sessions told Fox News, in an interview that will be aired Wednesday night. "The state of California is not entitled to block that activity."
California officials counter that they have the constitutional right to govern their state as they see fit. “States and local jurisdictions have the right to determine which policies are best for their communities,” California Attorney General Xavier Becerra (D) told The Washington Post's Matt Zapotosky on Tuesday night after the lawsuit dropped.
Jessica Vaughan, policy director at the conservative-leaning Center for Immigration Studies, said the government has a good chance to knock down California's policies, which are some of the most defiant laws on the books.
She points to a case conservatives recently lost to prove her point. When the Supreme Court knocked down most of a controversial Arizona immigration law in 2012, the justices upheld the government's broad authority to enforce federal immigration law. That could prove a powerful precedent in the California case by underscoring that federal law outweighs state law, Vaughan said. And that could have a chilling effect on other states that are considering laws like California's.
“I think they are very likely to succeed, ultimately, and that it will help resolve the issue of sanctuary cities once and for all,” she said.
But Somin isn't so sure the government has a strong case.
Take one of California's new laws, which limits what state law enforcement officials can tell federal officials about some suspected undocumented immigrants. U.S. law prohibits state governments from instructing their officials to not share immigration status with the federal government. But, Somin said, at least one court has decided that the federal law is unconstitutional, violating the 10th Amendment, which restricts the federal government's commandeering of state and local governments.
Another California law prohibits employers from letting federal immigration officials raid a workplace without a court order. There, Somin said, California isn't specifically violating a federal law, but there is a way to interpret a Supreme Court decision that says federal immigration law generally preempts most state immigration law. “So there is no federal law which specifically says private employers must allow ICE immigration raids anytime ICE wants one,” he said.
It's important to keep in mind the Justice Department is challenging only three specific laws in California. If it wanted to ban all “sanctuary jurisdictions,” it would have to play whack-a-mole and sue other states or municipalities with different laws.
“If the government wins this case, they can get rid of some sanctuary policies,” Somin said. “It doesn't mean they can get all of them.”
On the whole, this lawsuit is a strategically risky endeavor for the Trump administration. It just launched a high-profile lawsuit that it may lose, potentially empowering other states that want to defy the president to pass similar laws.
But since Trump has tried and failed to end sanctuary cities with the wave of his pen, taking California to court is the only viable option he's got.