Editor's note: This story was originally published in October and has been updated to reflect Trump’s reelection.

(CNN) — Former President Donald Trump has vowed he’ll kick millions of undocumented immigrants out of the US when he returns to power.

In the months since cheering supporters waved “mass deportation now” signs at the Republican National Convention, Trump and his surrogates have offered various visions for how they’ll achieve this goal. But they’ve left no doubt that it’s a top priority.

“As soon as I take the oath of office,” Trump said in July, “we will begin the largest deportation operation in the history of our country.”

“If you’re in the country illegally, you better be looking over your shoulder,” former Immigration and Customs Enforcement chief Tom Homan said as he warned that no one would be off the table.

Trump adviser Stephen Miller said the military would be involved.

And vice president-elect JD Vance said deporting criminals would be the administration’s initial focus.

Experts say any path the future Trump administration chooses will be complicated and costly, due to both the billions of dollars needed to fund mass deportation and the significant ripple effects that will hit the economy.

Here’s a look at some key facts and figures that explain why.

1.5 million

The number of deportations during Trump’s presidency, according to a Migration Policy Institute analysis of government statistics.

On the campaign trail and during his presidency, Trump vowed that deporting undocumented immigrants would be a priority, and claimed as many as 3 million criminals would be deported when he was in office. But ultimately, he deported far fewer people than he’d promised.

In one particularly high-profile instance, Trump announced a massive operation to deport millions of people would be happening imminently in the summer of 2019. While some arrests occurred, the large-scale raids never materialized.

The Biden administration is on pace to match the Trump administration’s deportation numbers, according to the Migration Policy Institute’s analysis.

“Look at the history of ICE and the Trump years, where there was no lack of political will to deport people,” says John Sandweg, an acting director of the agency during the Obama administration. “And the maximum amount they could do (in one year) was 267,000.”

Trump advisers and outside allies told CNN earlier this year that this time, they’ve mapped out a concrete pathway to rapidly implement his immigration policy plans — and lessons learned during his previous term in office have helped them do that.

Why wasn’t Trump able to deport more people when he was in office?

Experts noted then, as they note today, that high costs and complex logistics make mass deportation more complicated than campaign promises suggest.

“It’s nearly impossible to implement,” says Laura Collins, an immigration policy expert at the George W. Bush Presidential Center.

Sandweg says even deporting 1 million people in a year, something vice presidential candidate JD Vance has suggested would be the administration’s starting point, simply isn’t realistic.

“It’s selling a fantasy to people,” he says.

$10,900

The average cost of apprehending, detaining, processing and removing one undocumented immigrant from the United States in 2016, according to figures released by ICE at the time.

That year ICE also said the average cost of transporting one deportee to their home country was $1,978.

Since then, the costs have only grown, Sandweg says, because the migrants coming to the US are from a wider range of countries.

“Now we’re facing a larger migration from all over the world,” he says.

That means deportation flights are more expensive, and the logistics around them are more complicated.

So what would deporting the millions of undocumented immigrants living in the United States cost?

In 2015, an analysis Collins co-authored for the American Action Forum, a conservative think tank, estimated arresting and removing all undocumented immigrants from the US would cost at least $100 billion and take 20 years. Recent estimates from immigrant advocates calculated an even higher cost. If 1 million undocumented immigrants are deported per year, mass deportation could cost more than $960 billion over more than a decade, according to the American Immigration Council.

Both of those reports were based on estimates that the undocumented immigrant population is around 11 million people, and the assumption that about 20% of the population could choose to leave the US voluntarily. A Pew Research Center report in July noted the undocumented population has likely grown over the past two years.

$992 million

The amount the Department of Homeland Security budgeted for “soft-sided” temporary detention facilities along the border in fiscal year 2023.

Trump adviser Stephen Miller has said a mass deportation operation would require officials to build massive facilities for immigrant detentions that could hold some 70,000 people — more than 10 times the capacity of the seven soft-sided facilities in the 2023 budget. Miller has described the plan to build new detention space as “greater than any national infrastructure project we’ve done to date.”

Tom Homan, who led ICE during Trump’s first administration, has pushed back on such characterizations.

“It’s not going to be a mass sweep of neighborhoods. It’s not going to be building concentration camps. I’ve read it all. It’s ridiculous,” Homan told “60 Minutes” when asked to describe his vision last month. Instead, Homan said, operations would be more targeted in nature.

But experts say any increase in arrests will inevitably correlate with an increase in detention.

Operating a soft-sided shelter can cost up to $40 million a month, according to Jason Houser, a former ICE chief of staff.

“It’s not just about throwing up a tent,” he says. “I have to staff it, I have to put security there, I have to put doctors there, I have to have some sanitation there, I have to put medics there, I have to put childcare there.”

Using more space in state and local jail facilities rather than building new facilities would also come with a hefty price tag, Houser says.

“That’s going to be $300 or $350 a night,” he says.

And if deportations were increased to the level Trump has proposed, detention space isn’t the only thing that would need to grow, Sandweg says. The ICE workforce would need to dramatically increase in size.

“You are talking about an increase of five or six times in the size of ICE operations. … hiring thousands of new officers, building tens of thousands of new detention beds,” he says.

That would require Congress to authorize billions of dollars in additional spending — something Sandweg describes as “incredibly hard.”

And even if that happens, he says, the logistical steps and time needed to hire people and build facilities could easily stretch for an entire presidential term.

1,016 days

The average time it takes for a case to make its way through immigration court, according to the Transactional Records Access Clearinghouse at Syracuse University.

This can vary considerably depending on the court location and other factors. On a national level, the already-huge backlog of cases in immigration court has increased significantly during the Biden administration, more than doubling from nearly 1.3 million cases in January 2021 to more than 3.7 million cases today.

The overwhelmed immigration courts would likely slow down any effort to deport more people.

“There are still legal processes that we have to go through in order to remove somebody,” Collins says. “They have the right to mount a defense. … Just because you’re not a citizen doesn’t mean you don’t have legal rights in this country.”

After ICE arrests someone, lengthy delays in immigration court proceedings mean years can pass before a case is completed.

“It doesn’t matter how many people you arrest,” Sandweg says, “because the Constitution requires that they get due process, which means they have an opportunity to pitch their case to an immigration court.”

13

The number of countries deemed “recalcitrant” by the Department of Homeland Security as of 2020. That term applies to countries that generally won’t accept deportation flights or help provide travel documents to their citizens when the US wants to remove them.

The list at the time included China, Cuba, India, and Russia, according to the Migration Policy Institute.

Exactly which countries are on the list can fluctuate amid geopolitical turmoil and diplomatic pressure. During the first Trump administration, officials used visa sanctions to pressure some uncooperative countries to comply. During the Biden administration, officials negotiated with Mexican authorities to send some deportees from uncooperative countries there.

But agreements over deportation can be fragile. Venezuela, for example, had agreed to accept deportees, but the deal fell apart earlier this year, according to MPI.

It’s a significant issue that a new Trump administration would have to contend with for any major deportation operation, Houser says, particularly given that large numbers of migrants from those countries have come to the US in recent years.

“If they’re Cuban, they’re not going home. If they’re Venezuelan, they’re not going home,” Houser says.

Officials could negotiate deals for a third country to accept deportees, he said. But in the short term, it’s likely a second Trump administration would focus on nationalities that can be deported more quickly, Houser says. If higher numbers remain a priority, Houser says it’s also likely officials won’t focus as much on capturing criminals, because those arrests require more legwork and manpower.

“They’re going to grab the person that’s easily removable, because that will give them the numbers and the imagery,” he says.

4.4 million

The number of US citizens under the age of 18 with at least one undocumented parent, according to Pew Research Center estimates.

Immigrant rights advocates say this figure gets at one of the big impacts of any major deportation operation, noting that these children are often attending schools and are part of communities outside their households. And they point out that whether or not officials hit the higher numerical targets they’ve promised, the impact of any deportations on families and communities would be devastating.

We saw smaller-scale versions of what this can look like during the first Trump administration.

After ICE arrested nearly 700 people in raids at seven Mississippi chicken plants in 2019, a local gym opened its doors to kids who’d gotten off their school buses and discovered their parents were missing. TV crews filmed traumatized and desperate kids at the scene, pleading for authorities to release their parents.

After a meatpacking plant raid in rural Tennessee in 2018, 500 kids missed school the next day.

“It was like a bomb had gone off — helicopters flying overhead, children riding the bus home to empty homes, and families desperately trying to find information about their loved ones who were detained — and the effects on the community were felt for years,” says Lisa Sherman Luna, executive director of the Tennessee Immigrant and Refugee Rights Coalition.

Asked by “60 Minutes” whether there’s a way to carry out mass deportation without separating families, Homan offered a swift response.

“Of course there is,” he said. “Families can be deported together.”

8.3 million

The number of undocumented immigrants in the US workforce, according to the Pew Research Center. That’s 5% of the workforce. And the share of undocumented workers is particularly high in certain industries, including construction, agriculture and service.

Economists have been warning that any major deportation effort would have a significant impact far beyond any one particular workplace.

“The economy as a whole downsizes to the detriment of everyone,” says Michael Ettlinger, a senior fellow at the Carsey School of Public Policy at the University of New Hampshire.

“Removing people that we know are here and working would be shooting ourselves in the foot economically,” Collins says, noting that the impact of immigrant workers also includes what they spend, not just what they earn.

“Anyone who is here and working is also getting haircuts and eating at restaurants and buying groceries and doing lots of things that grow the economy more,” she says.

$96.7 billion

The estimated amount of taxes undocumented immigrants pay annually, according to the nonpartisan Institute on Taxation and Economic Policy.

According to Zeke Hernandez of the University of Pennsylvania’s Wharton School, such estimates show that undocumented immigrants make a significant contribution – something governments would miss out on if they’re deported. But Hernandez, author of “The Truth About Immigration: Why Successful Societies Welcome Newcomers,” argues that talking about the taxes these immigrants pay only paints part of the picture.

“The other tax that governments miss out on, which is usually not talked about, are the taxes that businesses would have paid had they been able to expand and grow. … When a business can’t hire and has to either contract or not grow, it will have less profits and less revenue, and therefore pay less in corporate taxes,” he says.

Critics of illegal immigration argue that the cost to US citizens is far outweighed by any taxes undocumented immigrants pay. The Federation for American Immigration Reform, which argues for increasing immigration restrictions, estimates Americans pay more than $150 billion annually due to illegal immigration.

The organization also argues that mass deportation would make more jobs available for Americans.

But Hernandez says history has shown that’s not the case.

A study based on an analysis of deportations that occurred during the Obama-era “Secure Communities” program, for example, indicates 88,000 US-born workers would lose jobs for every 1 million unauthorized immigrants deported.

Why would deportations hurt US-born workers?

Businesses end up investing less in growing or creating new companies, and more in technologies that replace lower-skilled workers, Hernandez says.

The recent study provides a telling example, he says, of how large-scale deportation efforts have ripple effects beyond immigrant communities. The economic impact of mass deportation, he says, would amount to “utter disaster.”

“We Americans, we, the country, we, in our communities, would be significantly damaged,” he says.

The-CNN-Wire
™ & © 2024 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.