Barriers to sending some immigrants home are among the legal and logistical obstacles President-elect Donald Trump faces as he pledges mass deportations

Nearly half of the 1.4 million people in the U.S. immigration system who have pending deportation orders cannot be sent back to their home countries, according to internal Immigration and Customs Enforcement data, posing one of several looming obstacles to President-elect Donald Trump’s pledge for a mass removal campaign.

Some orders can’t be carried out because the would-be deportee’s home country won’t take them or limits cooperation with ICE. Others identified for deportation are serving prison terms, or have received a reprieve or deferral from an immigration judge, due to a medical condition, a credible persecution threat or another extenuating factor.

An array of other logistical and legal impediments also could constrain mass deportations, according to current and former ICE officials.

Trump promises to brush aside hurdles and mount a campaign modeled after the harsh roundups of the Eisenhower Administration, when the U.S. government expelled hundreds of thousands of migrant workers to Mexico.

“We will begin — and we have no choice — the largest deportation operation in American history,” he said on the campaign trail.

Trump’s aides describe the anticipated campaign as an enforcement blitz that will leverage the power and resources of the U.S. military to roll back the effect of record numbers of illegal border crossings under President Joe Biden. Criminals and those with outstanding deportation orders will be the administration’s priority as of Trump’s inauguration, Jan. 20, aides say.

“It’s going to be at light speed,” Trump adviser Stephen Miller said on Fox News last month, “the moment President Trump puts his hand on that Bible and takes the oath of office.”

Republican lawmakers are seeking to move a spending bill through Congress early next year that would boost ICE’S budget and staffing levels. Trump may also seek to tap into Department of Defense funds, similar to the way he diverted $10 billion from Pentagon accounts during his first term, from 2017 to 2021, to pay for wall construction along the U.S.-Mexico border.

Some Trump supporters point to Operation Allies Welcome as a potential blueprint for their plans. The 2021 operation was the Biden administration’s “whole-of-government” effort to rescue and resettle nearly 100,000 Afghan refugees by temporarily housing them on military bases and enlisting federal employees from multiple agencies to help.

If the Biden administration can bring people into the country with military resources and efficiency, they argue, the incoming Trump administration can do the reverse to send people out.

But unlike the Afghan program, which rescued willing evacuees, Trump’s deportation efforts target people who do not want to leave this country. They have met determined resistance from immigrant advocates and lawyers.

During Trump’s first term, his administration tried to expand a form of fast-track deportation authority known as “expedited removal” that is limited to recent border-crossers. Trump’s attempt was blocked in U.S. District Court in 2019, then an appeals panel overruled the decision the following year. At that time, the coronavirus pandemic was in full swing and health protocols sought to limit crowding in detention centers to avoid spreading the infection.

Biden rescinded the nationwide expedited removal order in 2022. Trump is expected to reinstate it, allowing ICE to arrest and deport immigration violators without appeal. Even expedited deportations often require ICE to hold someone for weeks until arrangements for their trip home can be finalized.

Miller, who will return to the White House as Trump’s deputy chief of staff for policy, told the New York Times last year that the Trump administration could set up detention camps and temporary holding facilities until people are deported. He declined to comment for this article.

U.S. Customs and Border Protection in recent years has made extensive use of climate-controlled tent sites known as “soft-sided facilities” to temporarily hold and process migrants apprehended along the U.S.-Mexico border. Using these to detain deportees would pose significant safety risks to employees and contractors, according to current and former ICE officials.

ICE detainees may be desperate to avoid deportation, and emotionally distraught after separation from their families. Such detainees are generally less compliant than migrants who have recently crossed into the United States, ICE officials said, because the latter group retains some hope of being allowed to stay in the country.

“CBP has different detention standards,” said one retired ICE official who spoke on the condition of anonymity because they are considering a return to the agency to help fill staffing shortages. “ICE operates under a much higher bar, with a lot more requirements and services that need to be offered to a person in detention.”

Tom Homan, the former ICE acting director who Trump has designated as “border czar” to oversee the deportation campaign, told The Post last month that anyone with a removal order from an immigration judge could be deported, regardless of whether they had a criminal record.

“If those orders aren’t executed or carried out, then what the hell are we doing?” Homan said. “Nothing in immigration law says you need to commit a very serious criminal offense to be removed from the country.”

ICE officials will likely turn to private detention contractors to expand capacity beyond the current level of around 40,000 beds per day across a nationwide network of for-profit facilities and county jails. During Trump’s first administration ICE pushed its detainee population to about 55,000, and current and former ICE officials said it would not be difficult to return to similar capacity levels if funds were available.

Finding tens of thousands of additional beds would prove challenging, however, according to current and former ICE officials. Military bases have significant drawbacks, they said.

During Operation Allies Welcome, for instance, Afghans housed on military bases received benefits and incentives to remain. They were not formally detained. But the barracks where many were housed would not be up to ICE detention standards nor provide the physical security of a jail setting, according to current and former ICE officials.

These officials agreed Trump can significantly increase annual deportations through more aggressive enforcement, especially with a major increase in ICE funding and support from other federal forces, such as U.S. Marshals and National Guard troops in Republican-led states.

Officials said they expect the effort to yield results comparable to those of Trump’s first term, at least initially. Trump took office in 2017 promising “millions” of deportations but topped out at 347,250 ICE removals in fiscal 2019, according to the Office of Homeland Security Statistics. ICE’S highest one-year total was 432,228 deportations in 2013, DHS records show.

Since then, scores of cities, counties and other jurisdictions across the United States have adopted “sanctuary” policies that limit cooperation with ICE. Police departments in those jurisdictions generally do not help ICE carry out street-level arrests, and jails will not hold immigration violators charged with traffic offenses, or in some cases violent felonies.

Yet city and county jails remain the easiest place for the Trump administration to round up more potential deportees. By going into secure detention facilities, a relatively small team of ICE officers can take custody of multiple immigration violators, avoiding potentially volatile confrontations with the suspects and their family members, as well as the scrutiny of cellphone cameras.

ICE worksite raids or street-level arrests known as at-large operations typically require weeks of planning and coordination with local police departments. During those operations, ICE agents may sweep up suspected immigration violators aside from their targets, but the number of people ICE can detain and quickly deport is often much smaller than the number they arrest. Detainees have the right to request a hearing with an immigration judge, slowing or halting the deportation process.

“Going out and arresting people in the community is very difficult and resource intensive,” said one senior ICE official, who was not authorized to speak to reporters. “Without getting more cooperation from sanctuary jurisdictions, I see increases, but I don’t see crazy numbers.”

Trump aides say the incoming administration will immediately scrap Biden administration policies that have directed ICE to spare immigrants who are illegally in the country but don’t pose a safety threat.

ICE told lawmakers that as of July there were about 663,000 immigration violators in the United States with criminal convictions or charges who aren’t in ICE custody. That includes individuals serving sentences in federal or state prisons and others who may have been allowed to stay by an immigration judge, despite their deportation orders, because it was too dangerous or difficult to send them home.

Homan and other Trump aides said enforcement efforts will focus on rounding up criminals who remain at large.

ICE’S staffing levels aren’t adequate to carry out a mass enforcement campaign of that nature, current and former agency officials said. ICE has about 5,500 officers working on immigration cases. Hundreds of vacant positions remain unfilled. A funding boost won’t immediately increase staffing, because the average amount of time it takes to recruit, screen, train and deploy a new officer is 18 to 24 months, according to agency officials.

The number of people on ICE’s “non-detained docket” of immigrants whose cases it oversees has ballooned to 7.8 million, double the number it had in 2019, according to the latest figures, which include some of those with criminal records. The increase has been driven mostly by the record 2 million per year illegal crossings along the U.S.-Mexico border during Biden’s first three years in office.

About 1,100 ICE officers are assigned to ensuring immigrants on the non-detained docket comply with legal obligations. Current and former agency officials said many ICE officers will need to update their training before heading out on at-large operations and worksite enforcement raids, which Biden halted in 2021.

Taking potential deportees into custody is only the first step. Their home nations may not be prepared for mass receptions. Venezuela, Nicaragua and China are among several nations that limit or refuse to accept ICE deportation flights. During Trump’s first term his administration used diplomatic pressure — withholding visas, for example — to compel “recalcitrant” nations to accept more deportees.

Current and former ICE officials said even cooperative nations such as Guatemala and Honduras may not have space or staff to immediately issue landing permits for additional flights before the agency can show up with planeloads of deportees.

Aircraft availability presents another obstacle. ICE has at its disposal about a dozen charter planes, each with capacity for about 135 deportees, and charter companies don’t have a lot of additional aircraft sitting around, officials said.

Trump and his aides have discussed overcoming these limits by using military aircraft. Federal regulators would have to approve the use of military transport aircraft for civilian deportees. The Pentagon was not keen to play a role in immigration enforcement the last time Trump was in office, current and former ICE officials said, nor to share its transportation contracts.

“If you start using those planes for deportations, you quickly get into problems with military force readiness,” the retired ICE official said. “It’s the same contractors who are flying our service members to the Middle East or to Germany.”