Legal battles between the U.S. Department of Justice and so-called “sanctuary” jurisdictions have so far focused on federal grant money, but a lawsuit the department filed against California over its immigration laws may lead to a host of new lawsuits with municipalities that, like Philadelphia, limit local law enforcement's interactions with immigration officials.

On Tuesday, the DOJ sued California, Gov. Jerry Brown and Attorney General Xavier Becerra, seeking to block recently enacted state laws that limit what information local law enforcement officers can share with immigration officials.

Under President Donald Trump, the DOJ has been seeking to withhold federal grant money from Philadelphia and other municipalities that the federal government claims do not adhere to federal immigration policies. But the lawsuit against California presents a new line of attack for the Trump administration that, according to Temple University's Beasley School of Law professor Peter Spiro, could have significant implications for other sanctuary jurisdictions.

“If the Justice Department got a big win, you can bet they would aggressively pursue similar measures in other jurisdictions,” Spiro said.

According to Spiro, any impact the lawsuit may have on other sanctuary jurisdictions will depend greatly on how the case is viewed by the courts. However, if it is successful, municipalities like Philadelphia can expect to see an increase in similar lawsuits, Spiro said.

Pennsylvania is no stranger to clashes with the federal government over its immigration policies. Last year, U.S. Immigration and Customs Enforcement officials listed more than a dozen municipalities as sanctuary jurisdictions, and in August, Philadelphia sued U.S. Attorney General Jeff Sessions for threatening to withhold DOJ grant money over the city's immigration policies. In November, a federal judge determined the city was in compliance with federal law, and blocked efforts to withhold the money.

City officials were largely quiet Wednesday about how the lawsuit against California may affect Philadelphia. A spokesman for the Philadelphia Law Department and Mayor Jim Kenney, who has been a vocal supporter of sanctuary policies, declined to comment about the case, except to say the city is reviewing the lawsuit.

A spokesman for Philadelphia District Attorney Larry Krasner, who recently appointed an attorney to deal specifically with immigration issues that may arise for criminal defendants, deferred to the Law Department about what implications the California lawsuit may have for the city, but said Krasner ”strongly supports Philadelphia remaining a sanctuary city.”

“It's outrageous that the federal government is working to actively target certain communities without recognizing the consequences for local law enforcement,” spokesman Ben Waxman said in an emailed statement.

The suit against California deals largely with arguments about federal supremacy over state laws, and, according to Spiro, the courts could either delve into the minutia of California's immigration laws, or rule more broadly on the issue. The broader the eventual court ruling, the more likely it could apply to other sanctuary municipalities.

“One thing to remember at the top is California has its own particular statutes that are being challenged, and those are different than the ones Philadelphia has,” Spiro said. “There may be aspects of the California law that makes it more vulnerable to it than other sanctuary jurisdictions.”

The DOJ's lawsuit challenges SB 54, the so-called “sanctuary state” law that limits state law enforcement interactions and information sharing with immigration authorities; AB 450, which bars private employers from cooperating with immigration agents in certain ways; and AB 103, which allows the state attorney general to inspect federal immigration detention facilities. Brown signed each of the bills into law last year.

The suit does not present the first time disputes have arisen about the supremacy of federal over state immigration laws. However, those disputes have often arisen where state law imposes more, rather than less, strict immigration policies.

Raising similar federal-supremacy arguments, the DOJ under President Barack Obama sued Arizona over its 2010 immigration laws. That case resulted in the U.S. Supreme Court striking down portions of the law, but leaving in place its most controversial provision, which allowed police to check the immigration status of people they detained. Justice Anthony Kennedy wrote the court's majority opinion, saying the government has “significant power to regulate immigration.”

If successful, the federal supremacy argument could have significant ramifications for sanctuary jurisdictions, Spiro said.

“That principle is one they're trying to deploy against all sanctuary jurisdictions. As a political matter at the very least,” Spiro said.

“On the other hand, if they lose, then it's just going to be another way in which their aggressive enforcement action is being stymied in the courts,” Spiro said, citing the DOJ's recent setbacks trying to impose a travel ban on several countries and dismantle the Deferred Action for Childhood Arrivals program.