Connecticut immigration groups are preparing for a fight over President-elect Donald Trump’s promise of “mass deportations” for undocumented migrants.

The effort is likely to face serious legal hurdles, especially in Connecticut, experts said.

Within minutes of declaring victory Wednesday morning, the incoming president promised a major immigration crackdown.

“We’re going to have to seal up those borders,” Trump told supporters in Florida.

Trump has pledged to round up millions of undocumented migrants – using the military if necessary.

“We have to take them out,” Trump told News 12 in May. “We have to get them out of the country. We have to deport them.”

While Trump and his advisers have offered outlines, many questions remain about how they would deport anywhere close to the 11 million people estimated to be in the country illegally. How would immigrants be identified? Where would they be detained? What if their countries refuse to take them back? Where would Trump find money and trained officers to carry out their deportation?

Trump, who repeatedly referred to immigrants “poisoning the blood” of the United States, has stricken fear in immigrant communities with words alone. But in Connecticut, large-scale deportations will not be easy. Immigration advocates are already lawyering-up.

“More lawyers, more legal workers,” said Susan Schnitzer, president of the Connecticut Institute for Refugees and Immigrants in Bridgeport. “We are concerned – primarily concerned not only with the safety of our clients, but of refugees and immigrants across the nation.”

Schnitzer said most migrants can challenge deportation orders in court, although she cautioned that a Republican-controlled Congress could change immigration laws.

“People confuse ‘undocumented’ meaning that there’s no pathway to temporary or permanent status here in the U.S.,” said Schnitzer. “It’s far more nuanced than that.”

Connecticut was home to an estimated 113,000 undocumented people as of 2019, according to the Migration Policy Institute. Most come from Mexico, Guatemala, Brazil, Ecuador and India.

The state’s TRUST Act prohibits local law enforcement from rounding them up.

“Police are prohibited from taking people into custody based simply on a suspicion that they might be undocumented,” said Mike Lawlor, a criminal justice adviser to former Gov. Dannel Malloy, who now teaches at the University of New Haven. “Unless there’s a warrant signed by a judge, which is the same rule that governs all the rest of us, right? Or if they’re on the terrorist watch list or if they’ve previously been convicted of a serious felony.”

Trump has said he would invoke the Alien Enemies Act, a rarely used 1798 law that allows the president to deport any noncitizen from a country the U.S. is at war with. He has spoken about deploying the National Guard, which can be activated on orders from a governor. Stephen Miller, a top Trump adviser, has said troops under sympathetic Republican governors would send troops to nearby states that refuse to participate.

Trump has also threatened to withhold federal funding from so-called "sanctuary cities" like New Haven if they don’t cooperate with immigration authorities. But that did not happen during his first term.