WASHINGTON — President-elect Donald Trump says in order to carry out his ambitious promise of mass deportations, he will have to draw on the resources of the U.S. military. Legal experts say how troops can be used for immigration enforcement operations hinges on how exactly the country’s armed forces would be used and whether they will be asked to directly engage with undocumented immigrants.

What You Need To Know

  • President-elect Donald Trump suggests using U.S. military resources for mass deportations, possibly invoking centuries-old laws in a move that could face significant legal challenges

  • Federal law generally restricts military involvement in domestic law enforcement, and experts argue that declaring an “invasion” to justify such declarations would require evidence of foreign military activity, not just migrant crossings

  • Some Democrats warn that deploying the military for immigration enforcement could harm affected communities and military agencies, with financial costs and other trade-offs because military resources would be redirected from other duties 

Two years ago, Republican Texas Gov. Greg Abbott declared that migrants crossing the border from Mexico constituted an invasion so he could deploy the National Guard to protect the state.

Trump has threatened to do something similar in order to use U.S. troops for immigration enforcement.

Last week, Trump responded with the word “TRUE!!!” to a social media post that said the incoming Trump administration is preparing to “declare a national emergency and will use military assets” to carry out a mass deportation program. 

“I'll wait and see what the administration proposes, and we'll judge on its merits. but we need to carry it out,” Rep. Chip Roy, R-Austin, told Spectrum News.

Under Republican and Democratic administrations, the Department of Defense has provided operational support to Customs and Border Protection officers. The military has not conducted raids or arrests of undocumented immigrants because federal law largely bars the use of U.S. troops for domestic law enforcement.

But during this year’s campaign, Trump and his hardline immigration adviser, Stephen Miller, have suggested that centuries-old laws could be used to deputize U.S. troops as immigration officers in order to arrest and deport undocumented immigrants suspected of crimes. 

“I will invoke the Alien Enemies Act of 1798,” Trump said at a rally last month in Madison Square Garden in New York.

Doing so may trigger lawsuits challenging the legality of such actions.

“He would have to declare an emergency based on an invasion of one particular foreign country. An invasion, when you look at it historically, it means an invasion that's a military action by a foreign state, not just people from that state. So in other words, it would have to be the military of Nicaragua, Guatemala, Haiti, Venezuela that is invading the United States for that act to trigger. If you look at the act, it doesn't just mean someone crossing an imaginary line in the desert with a jug of water in their hand. It means someone crossing that same line wearing a military uniform with weapons,” immigration attorney George Lobb told Spectrum News.

Democrats in Washington are already on edge in anticipation of the Republican trifecta next year – the GOP controlling the White House and both chambers of Congress.

“When you use our military or our law enforcement for missions that they are not trained for, missions that they should not be doing, it is harmful, not just to the populations impacted by those missions, but it's harmful to those agencies as well,” Rep. Veronica Escobar, D-El Paso, said.

It is unclear how exactly the military would be deployed and carrying out mass deportations would likely cost many billions of dollars, although Trump has said cost would not be an issue. There could also be potential trade-offs, as the military would be redirected from other duties.