On the eve of a visit by President Trump to New Jersey for a major campaign rally, his administration has unexpectedly intervened on behalf of local officials in the state over a volatile immigration dispute.
The Justice Department on Friday joined a lawsuit that seeks to overturn a state directive that limits how much local law enforcement can cooperate with federal immigration authorities. The move falls in line with the Trump Administration’s escalating efforts against so-called sanctuary policies around the country.
The two counties who filed the suit are in the district of Representative Jeff Van Drew, a freshman centrist who was elected as a Democrat but recently became a Republican after voting against impeaching President Trump.
In changing parties, Mr. Van Drew pledged “undying support” for Mr. Trump. Mr. Van Drew’s decision has roiled the political landscape in the southern part of the state and raised the stakes for his re-election campaign.
Amy Kennedy, the wife of former Representative Patrick Kennedy, part of the political dynasty, announced this month that she would join the crowded race against Mr. Van Drew, releasing a video that included images of him meeting with the president in the Oval Office after announcing his switch. Mr. Trump announced Tuesday’s rally that same day.
The Justice Department’s decision to side with the two counties may signal that Mr. Van Drew — who will speak at Mr. Trump’s rally on Tuesday night in Wildwood — intends to make immigration a central plank in his re-election campaign, just as Mr. Trump has done.
Mr. Van Drew did not immediately respond to requests for comment.
Mr. Trump’s appearance at the Wildwood Convention Center is his first campaign rally in the state as president, though he frequently has visited his golf courses there.
New Jersey has tended recently to vote Democratic, voting overwhelmingly for Hillary Clinton in 2016. The party also controls both the governor’s office and the Legislature. But the rally will take place in a more conservative area in the southern part of the state that is more friendly to Republicans.
The rally is expected to draw thousands of Trump supporters, including from out of state. Mr. Van Drew told Fox News that 100,000 tickets had been requested for the event at the venue, which holds 7,400 people.
At issue in the lawsuit is the New Jersey attorney general’s Immigrant Trust Directive, which the Justice Department is asking be declared unconstitutional. They are not a party in the lawsuit, but will be supporting the counties’ efforts.
The Justice Department did not immediately respond to requests for comment.
In an emailed statement, a spokeswoman for the Trump campaign declined to comment.
The state attorney general, Gurbir S. Grewal, said in a statement on Saturday that he was “deeply disappointed” that federal officials “have suddenly chosen to challenge” the directive in court.
Mr. Grewal said the directive had played an important role in “ensuring that victims and witnesses come forward and report crimes to law enforcement without fear of deportation.”
He added: “The federal government’s efforts to coerce states into implementing its immigration agenda have failed repeatedly in the past, and we’ll respond to their latest efforts in court at the appropriate time.”
Introduced in November 2018, the state attorney general’s directive limits the extent to which local and state law enforcement can assist federal civil immigration enforcement efforts. It restricts sharing information with federal authorities and prohibits law enforcement from stopping or questioning individuals based on their immigration status.
Cape May County and Ocean County filed separate lawsuits opposing the directive, but those lawsuits were consolidated before the Justice Department got involved in the suit.
State Senator Michael Testa Jr., a Republican who is one of the lawyers who filed the lawsuit on behalf of Cape May County, said he had not been consulted about the Justice Department’s decision.
But he criticized the limits the directive places on local law enforcement officers’ ability to cooperate with United States Immigration and Customs Enforcement, or ICE.
“I really don’t understand why our attorney general would not want to have coordination between law enforcement agencies at the county level, with ICE, when an individual who is here in this country illegally has in fact committed a crime,” said Mr. Testa, who is an honorary chairman of Mr. Trump’s re-election campaign in New Jersey.
Critics have called the directive the Sanctuary State law, a framing that the attorney general has rejected.
Most local law enforcement officers in the state have supported the directive, saying that local authorities should not be asked to enforce federal immigration law and that the directive has helped them to maintain the trust of immigrant communities in their efforts to fight crime.
The pushback has been centered in South Jersey, including Cape May County, where Mr. Trump will be supporting Mr. Van Drew this week.
Tracey Tully contributed reporting.