As Donald Trump promises largest mass deportation of undocumented immigrants in U.S. history if re-elected, his team plans to deny federal police funding to local law enforcement agencies who refuse to participate in the evictions, three sources close to the Trump campaign told NBC. News.

The move could lead to legal challenges, as a similar policy did under the first Trump administration. The sources also cautioned that no plans are set in stone until Trump announces them himself.

The Trump campaign did not respond to requests for comment.

All three sources close to the campaign said the tactic would survive legal challenges and put pressure on blue states, counties and cities to participate in mass evictions.

Ron Vitiello, who was acting director of Immigration and Customs Enforcement during Trump’s first term, recalled the deep frustration of administration officials when protracted court battles with Democratic-controlled states and cities stalled Trump’s plan.

“The Department of Justice was going to withhold the grant money,” Vitiello told NBC News. “They weren’t able to enjoy it, if you will, or participate fully in it.”

So-called sanctuary cities, like Chicago, and states, like California, currently refuse to alert ICE when they encounter or arrest undocumented immigrants. When undocumented immigrants complete their sentences in state or local prisons, they are typically released into the community rather than turned over to ICE.

Trump promised that if he returned to power, he would immediately begin rounding up undocumented immigrants across the country, starting with those with criminal records or final orders of deportation.

Nearly 1.5 million immigrants in the United States have been subject to final orders of deportation, according to ICE officials. And more than 430,000 immigrants with criminal records are believed to be living in the country outside of ICE detention facilities. It is unclear to what extent the two groups overlap.

Under the first Trump administration, more than 400,000 immigrants with criminal records lived in the United States outside of ICE detention centers, roughly the same number as during the Biden-Harris administration.

According to the American Immigration Council, a pro-immigration research and advocacy organization, asking federal agents to arrest and deport up to 1.9 million of these immigrants would cost nearly 10 times the current annual budget. ‘ICE.

To pressure local law enforcement to cooperate, the Trump team would cut off their access to Justice Department grants, the three sources said. The Justice Department describes the grants, known as the Byrne JAG Grant Program, as the “primary source of federal justice funding for state and local jurisdictions.”

The Department of Justice has consistently awarded more than $250 million in funding annually to state and local law enforcement agencies through the Byrne JAG Grant Program. The process is competitive and law enforcement agencies have used the funding to cover the costs of policing, drug treatment centers and correctional programs.

During Trump’s first term, several states, including New York, sued the administration after it eliminated Byrne JAG grants to sanctuary cities. After an appeals court ruled in favor of the Trump administration, Democratic-controlled states appealed to the Supreme Court. And this legal maneuver, in essence, wasted time for the first Trump administration.

Before the Supreme Court ruled, Joe Biden won the 2020 election, took office, and revived the sanctuary city grant program. Trump campaign officials say they are confident they can quickly challenge their decision before the Supreme Court and that the high court’s large conservative majority will support them.

Vitiello said a second Trump administration would also provide additional funding to state and local police departments that participate in mass evictions.

“I could see, under the administration, an incentive,” Vitiello said. “Or a way to gain leverage for those who don’t want to comply.”