Inside Trump's plan for mass deportations - and who wants to stop him

Donald Trump is expected to mobilise agencies across the US government to help him deport record numbers of immigrants, building on efforts in his first term to tap all available resources and pressure so-called "sanctuary" jurisdictions to cooperate, according to six former Trump officials and allies.

Trump has defeated Democrat Kamala Harris in a stunning political comeback, Edison Research projected, telling supporters America had given him an "unprecedented and powerful mandate".

Trump backers - including some who could enter his second administration - anticipate the Republican president-elect will call on everyone from the US military to diplomats overseas to turn his campaign promise of mass deportations into a reality. The effort would include cooperation with Republican-led states and use federal funding as leverage against resistant jurisdictions.

Trump recaptured the White House vowing a vast immigration crackdown. The centrepiece of his reelection bid was a promise to deport record numbers of immigrants, an operation Trump's running mate JD Vance estimated could remove 1 million people per year. Immigrant advocates warn that Trump's deportation effort would be costly, divisive and inhumane, leading to family separations and devastating communities.

Edison Research exit polls showed 39 percent of voters said most immigrants in the US illegally should be deported while 56 percent said they should be allowed to apply for legal status.

Trump struggled to ramp up deportations during his 2017-2021 presidency. When counting both immigration removals and faster "returns" to Mexico by US border officials, Biden deported more immigrants in fiscal year 2023 than any Trump year, according to government data.

But a deportation operation targeting millions would require many more officers, detention beds and immigration court judges. American Immigration Council, an immigrant advocacy group, estimated the cost of deporting 13 million immigrants in the US illegally as US$968 billion (NZ$1,628 bn) over a little more than a decade.

Tom Homan, a former acting director of US Immigration and Customs Enforcement (ICE) expected to join the new administration, said in a late October interview that the scale of the deportations would hinge on potential officers and detention space.

"It all depends on what the budget is," he said.

While the incoming Trump administration could benefit from experience gained during his first term, it could again encounter resistance from ideologically opposed government employees, including officers that screen migrants for asylum.

The American Civil Liberties Union and immigrant advocacy groups have been preparing for court battles if Trump again tests the bounds of his legal authority. Lee Gelernt, an ACLU attorney who led the fight against Trump's contentious family separation policy, said more than 15 lawyers focused on immigration with the organization's national office spent the year readying for the possibility of a Trump return.

"We definitely need to be co-ordinated and have more resources, because I think they will come in much more prepared," Gelernt said.

The State Department in particular could be one place where Trump acts more aggressively than during his first term, several Trump backers said. A key factor will be whether other countries will accept their citizens, an issue Trump faced with limited success during his first term. The Trump administration also struggled at times to convince other nations in the region - including Mexico - to take steps to stop migrants from moving toward the US-Mexico border.

Ken Cuccinelli, former acting deputy secretary of the US Department of Homeland Security under Trump, said the State Department was a "roadblock" for immigration enforcement and that aggressive appointees will be key.

Christopher Landau, a former US ambassador to Mexico from 2019-2021, recently said he was frustrated with the reluctance of some US diplomats to tackle immigration enforcement.

"Nobody really thought that was their problem," Landau said in an October panel discussion by the Center for Immigration Studies, which favours restricting immigration.

About half of ICE's 21,000 employees are part of its Homeland Security Investigations unit, which focuses on transnational crime such as drug smuggling and child exploitation rather than immigration enforcement. Several Trump allies said the unit would need to spend more time on immigration.

HSI has distanced itself from ICE's immigration work in recent years, saying fear of deportation made it harder for its investigators to build trust in immigrant communities. Stephen Miller, the architect of Trump's first-term immigration agenda, said in 2023 that National Guard troops from cooperative states could potentially be deployed to resistant states to assist with deportations, which would likely trigger legal battles.

Trump plans to use a 1798 wartime statute known as the Alien Enemies Act to rapidly deport alleged gang members, an action that would almost certainly be challenged in court.

The law has been used three times, according to the left-leaning Brennan Center for Justice: the War of 1812, World War One, and World War Two, when it was employed to justify internment camps for people of Japanese, German and Italian descent.

The Brennan Center and others have called on Congress to repeal the law.

"Many fear that a second Trump administration would seek to use this law to justify indefinite detention and remove people from the country swiftly and without judicial review," Naureen Shah, the ACLU's deputy director of government affairs, wrote in late October.

George Fishman, a former DHS official under Trump, said the Trump administration would need to prove the immigrants were sent by a foreign government.

"I worry a little about overpromising," Fishman said.

- Reuters