Boston attorney John P. Foley has practiced immigration law for more than three decades. In recent months, he has become a frequent voice in Irish media, including a mid-February appearance on RTÉ television, discussing the changing enforcement landscape in the United States.

In an interview last month with Boston Irish, Foley described what he sees as a significantly more aggressive federal immigration system — one that has left undocumented immigrants, lawful residents, and even US citizens uneasy.

“There’s not much many of them can do,” Foley said of Irish nationals who have overstayed visas. “Most came in on the Visa Waiver or ESTA program and have overstayed, some by a significant amount of time. Once someone overstays by more than a year, if they depart the United States, they’re automatically barred from returning for 10 years. That’s why they’re stuck here.”

His advice is stark: keep a low profile. “Don’t do anything that puts you in front of law enforcement. Stay out of trouble,” he said. “There’s not much you can do to erase yourself from the system.”

While Immigration and Customs Enforcement (ICE) has not yet focused heavily on Visa Waiver overstays, Foley believes that could change. “They are low-hanging fruit,” he said. “I think that will change sooner rather than later.”

He points to a dramatic rise in detention numbers as evidence of a broader crackdown. For the first time in US history, he noted, the number of individuals in ICE custody has surpassed 70,000, reaching approximately 73,000 detainees — roughly the population of Somerville or Newton.

There are now more than 200 active ICE detention facilities nationwide, a number that has doubled in recent years. The administration has outlined plans for a “hub-and-spoke” detention model, including regional processing centers for short-term stays and large-scale facilities for longer-term detention, some created from converted warehouses.

“It’s a mean-spirited plan,” Foley said. “It has created fear, and none of it makes us safer as a community.”

One of the most troubling aspects, he said, is the speed and distance with which detainees are transferred. A person arrested in Massachusetts might be processed locally, then moved to upstate New York and within days flown to Texas or Louisiana.

“It’s already difficult to represent someone in ICE detention,” Foley said. “It’s even harder when they’re 3,000 miles away.”

Although immigration law is federal and attorneys can represent clients nationwide, the logistics complicate cases. Lawyers often need local counsel for filings. Communication becomes more difficult. Access to detainees is limited.

“The policy of transferring detainees thousands of miles away adds frustration and reduces the chances of a favorable result,” he said.

Foley noted that clients held in southern facilities report overcrowding, poor hygiene, inadequate medical care, and low-quality food. Some describe being placed in cells with 20 or more men.

At the same time, he said, authorities appear less willing to release detainees under supervision. In previous years, individuals with viable legal claims might have been released on electronic ankle monitors while their cases proceeded. That is happening less frequently now.

In addition to the more than 70,000 people in physical detention, Foley estimates another 180,000 individuals are under electronic ICE monitoring.

As for the undocumented Irish population, estimates range between 8,000 and 15,000 nationwide, though Foley suspects the number may be higher. Federal data show that fewer than one percent of Visa Waiver entrants overstay, but that still amounts to tens of thousands of individuals from 43 participating countries. The United Kingdom leads in overstays, followed by Spain and Chile, with Ireland in the middle range.

One advantage Irish nationals have, Foley noted, is strong diplomatic engagement. The Irish Embassy in Washington and Irish consulates are often quick to respond when citizens are detained — assistance not always available to immigrants from other countries.

For those who are eligible to adjust their status through family sponsorship or other legal avenues, the path remains open. Individuals who become lawful permanent residents through marriage to a US citizen can apply for citizenship after three years instead of five.

Still, Foley says anxiety extends beyond the undocumented community. He recently heard from a man who became a US citizen 15 years ago but was hesitant to travel abroad because of a decades-old DUI conviction.

“I reassured him that as a citizen, he’s not at risk for something like that,” Foley said. “But he still wanted a travel letter in case of secondary inspection.”

That fear, he said, is widespread.