United States President-elect Donald Trump has confirmed he is “prepared” to declare a national emergency and use military assets to fulfil his 2024 election campaign promise to carry out mass deportations.

Trump announced on Monday in a short post on his Truth Social platform in response to a post by Tom Fitton, president of the conservative group Judicial Watch.

Fitton had written on November 8 that reports showed the incoming Trump administration was “prepared to declare a national emergency and will use military assets” in its “mass deportation” push.

Trump replied: “True!!!”

The statement is the firmest message yet on how Trump plans to fulfil his campaign promise to conduct the “largest deportation operation” in US history.

The effort has spurred condemnation from rights advocates and raised questions about the feasibility and the limits of Trump’s power as president to remove millions of undocumented immigrants from the country.

The Republican president-elect is also all but assured to face a mountain of legal challenges however he proceeds.

Aaron Reichlin-Melnick, a senior fellow at the American Immigration Council, said on Monday that under US law, presidents may declare a national emergency and exert emergency powers only in specific situations.

“And ‘use the military for deportations’ isn’t one of those specific things,” Reichlin-Melnick wrote on social media in response to Trump’s remarks.

Unanswered questions

While Trump has been making the deportation pledge for months as he zeroed in on the issue of immigration during his successful re-election campaign, he has offered few details on how he intends to carry out his plans once he assumes office in January.

An estimated 11 million to 13 million undocumented residents live in the US, and immigration and human rights groups have long warned of the humanitarian fallout of a mass deportation effort.

They have said such a policy would likely require an enormous and costly increase in enforcement and detention capacities.

An analysis by the American Immigration Council found that scaling up deportations to one million people a year – about four times the current rate – would cost $967.9bn over a decade.

Stephen Miller, Trump’s incoming deputy chief of staff for policy and longtime adviser on hardline immigration policies, has previously floated the idea of “deputising” the US National Guard, a branch of the military, to carry out large-scale raids and detentions.

Tom Homan, the former head of US Immigration and Customs Enforcement (ICE) who has since been tapped to be Trump’s new “border czar”, recently told the CBS TV programme 60 Minutes that the administration would use “targeted enforcement”.

Homan said in the interview at the end of October that the emphasis would be on work sites and “public safety threats and national security threats”.

To avoid family separations, Holman added: “Families can be deported together.”

Meanwhile, on the campaign trail, Trump regularly promised to invoke the Alien Enemies Act of 1798 – a law that allows presidents to deport citizens of an “enemy nation” without the typical proceedings – when speaking about his deportation plans.

But legal experts have said he does not have the authority to use the law for mass deportations.

On Monday, Reichlin-Melnick noted that Trump declared a national emergency in 2019 during his first term as president to unlock military funding for a border wall.

He said the president-elect may be planning to use a similar manoeuvre to unlock military funds for deportation enforcement but cautioned that Trump’s remarks should be taken with a grain of salt.

“My lesson from the first time around is that we absolutely cannot take things that the Trumpworld people say as gospel, given their total lack of specifics and total willingness to make grandiose pronouncements that are aimed at triggering the libs [liberals] and making headlines.”