This morning’s edition dives into the promises President-elect Donald Trump has said he will fulfill in his second term. NPR’s Steve Inskeep asks immigration policy expert Andrew Selee about Trump’s pledge to deport millions of immigrants.

What Trump said about deporting immigrants

During the campaign, President-elect Donald Trump promised “On day one, I will launch the largest criminal deportation program in American history.” He referred to “Operation Wetback” in 1954, an effort ordered by President Dwight D. Eisenhower. Government estimates showed that more than a million immigrants, mostly Mexicans, and some American citizens were rounded up. The program got its official name from a racist term for Mexicans who swam or crossed the Rio Grande.

He also said he would use the Alien Enemies Act of 1798 to precipitate the removal of undocumented migrants from the US and to “dismantle every criminal migrant network operating on American soil” at an Oct. 25 campaign rally.

Trump could start by trying to weed out new arrivals and expand deportation rules

Andrew Selee, president of the Migration Policy Institute, said Trump’s mass deportation plan could begin by removing hundreds of thousands of new arrivals admitted under programs established by President Biden.

“The first thing we know he’s going to do almost certainly is to revoke parole for people who have received it, people who came through CBP One, this application that people use to make an appointment to come across the border Selee said.

He also raised the possibility that Trump could go after people with Temporary Protected Status, a limited status given to people displaced from their home countries due to extreme circumstances and people admitted under a program offered to Cubans, Venezuelans, Haitians, and Nicaraguans.

Selee also said Trump could change deportation guidelines for Immigration and Customs Enforcement so the agency can more freely arrest and place undocumented immigrants in deportation proceedings.

“That’s something that changed under the Biden administration, where they were primarily going after people who had criminal records or people who are a threat to national security,” Selee said.

Selee also says that Trump has talked about expanding detention facilities, “But if he’s going to be able to use military bases or not or other federal facilities and if he’s going to try to use the military itself, and that would require going back to the (Alien Enemies Act of 1798) .”

Trump could argue for using the more than 200-year-old law to nullify due process and justify the use of military support to arrest and detain people without legal status.

Selee added that people living in Republican-controlled states are much more likely to see enforcement action.

“We saw that during the last Trump administration. There have been very successful enforcement efforts against people who are here illegally in red states because local law enforcement has been willing to cooperate,” Selee said.

He added that while law enforcement in blue states has not outright refused to cooperate, they have not invested large amounts of resources in working with immigration authorities.

What Trump’s team says

NPR asked Trump’s transition team if the president-elect has more specific details on how his plan to carry out mass deportations will begin. Trump transition spokeswoman Karoline Leavitt offered the following statement in response:

“The American people re-elected President Trump by a resounding margin, giving him the mandate to implement the promises he made on the campaign trail. It will be fulfilled.”

Trump’s appointments signal the seriousness of his enforcement actions

This week, Trump announced that he would Tom Homan his “border czar” who oversaw the US’s northern and southern borders. Homan led ICE in an acting capacity for about a year and a half during his first term. Border czar is not an official cabinet position, and it is unclear exactly what role Homan would have.

Before the election, Homan said enforcement would focus on immigrants who pose “threats to public safety and threats to national security first and foremost.” He also indicated that more raids could take place at the workplace.

A CBS journalist Homan asked during an October interview whether family separations could be avoided during mass deportations, particularly of US citizen children with undocumented parents. Homan responded by saying “Families can be deported together.”

Trump also announced the expected return of Stephen Millerthe immigration restrictionist who is seen as the architect Muslim travel ban and the controversial “zero tolerance” policy that separated thousands of children from their parents at the southern border. The reunification of approximately 1,400 children with their families had not been confirmed starting from April this year.

South Dakota Governor Kristi Noem he was also tapped to lead Homeland Securitythe cabinet that oversees immigration benefits and law enforcement. Noem has deployed National Guard troops to the US-Mexico border several times in recent years.