In the last month of the presidential campaign, former President Donald Trump is doubling down on his promise to carry out the largest mass deportation effort in American history. 

In Reading, Pennsylvania, last week, Trump drew fervent applause from a rally crowd after saying he would “get these people out” and “deport them so rapidly.” In Aurora, Colorado, on Friday, Trump told rallygoers he would “rescue Aurora and every town that has been invaded and conquered.” 

Immigration researchers, lawyers, and economists have pointed to immense constitutional, humanitarian and economic problems posed by Trump’s oft-repeated pledge. But beyond the anticipated damage to immigrant families, communities and local economies, the roundup and deportation of some 11 million people is near impossible to bankroll, according to an analysis of U.S. budget and immigration court data by CBS News. 

Even if Congress approved the hundreds of billions of dollars in spending, deporting every undocumented immigrant living in the U.S. would take far longer than four years, the analysis finds.

CBS News’ analysis of immigration system data found:

• Apprehending and deporting just 1 million people could cost taxpayers about $20 billion.
• Deporting 11 million people over four years would cost more than 20 times what the nation spent a year over the last five years on deporting people living in the U.S. Most of that would be new funding that would have to be approved by a majority of both chambers of Congress.
• Assuming Trump did get the funding and could rapidly expand the staffing in immigration enforcement and courts, the backlog of cases would grow — not decrease — by millions of cases based on what’s happened in the last two administrations.
• Trump’s own administration, despite promising to deport millions in 2016, deported 325,660 people during the fiscal years he was in office.

The cost of deportation to taxpayers

Over the last five fiscal years, it cost an estimated average of $19,599 to deport one person, according to a CBS News analysis of federal data. That figure is based on budget allocations for each step of the deportation process: the apprehension of an undocumented immigrant living in the U.S., detention, the immigration court process and transport out of the country. 

From 2021 to 2023, as migrant crossings at the southern border reached record highs, Immigration and Customs Enforcement deployed roughly a sixth of its workforce typically dedicated to deportation to the border to assist Customs and Border Patrol. (Crossings have since declined.)

ICE also diverted resources to removals under Title 42, an emergency health authority enacted during the pandemic that allowed border patrol to turn away migrants attempting to cross the border. Fewer people were deported from the interior of the U.S. during those years than in prior years, which drove up the cost per deportation. 

But even when Trump was president and the number of border crossings was lower than they were during the post-pandemic spike, the cost of deporting one person was still $14,614. To deport all 11 million undocumented immigrants estimated to be living in the U.S. at that time would have cost between $40 billion to $54 billion a year over the next presidential term — up to $216 billion total. ICE was allocated only $9 billion last year.

Even the lower end of that annual estimate, $40 billion, is enough to provide 20 million families each with a Child Tax Credit each year, and is more than double the Federal Emergency Management Agency’s entire budget. Over four years, the sum — $160 to $216 billion — is comparable to the cost of constructing around half a million new homes across the country. 

A similar analysis from the American Immigration Council put the total cost of deporting 11 million people even higher, at $315 billion.

“It can’t possibly be anywhere near 11 million”

Trump has said that local law enforcement will help with mass deportation since “they know their names, they know their serial numbers.” Experts say it’s not so simple. 

“One of the assumptions in the Trump proposal is that those local police and sheriffs are going to cooperate,” said Abigail Andrews, director of the Center for Comparative Immigration Studies at the University of California, San Diego. “We know from the last couple of decades that one of the major ways for cities and states to dissent around immigration processes has been for the police to cooperate or not cooperate with ICE.” 

Trump has said he would deploy the National Guard to identify and detain immigrants who have entered illegally. That plan could face legal barriers, since the law prohibits the use of federal troops for civilian law enforcement unless authorized by Congress. Trump responded to this by arguing that undocumented immigrants “aren’t civilians.” 

Enforcement agents could also end up racially profiling citizens and noncitizens alike in an attempt to identify undocumented immigrants living in the U.S. 

“There’s no way to do this without major civil liberties violations,” said Donald Kerwin, editor and founder of the Journal on Migration and Human Security. “At the end of the day, it can’t possibly be anywhere near 11 million.”

Trump promised a mass deportation when he ran for office in 2016, but during the fiscal years that ran through his term, ICE deported only 325,660 people from the interior of the U.S.

A mass deportation, depending on its scale, likely wouldn’t be complete in four years, either. Immigration courts in the U.S. currently face a backlog of 3.7 million cases, according to records obtained by Syracuse University. It would take the immigration court system eight more years and 700 additional judges — almost double its existing workforce — to eliminate the existing backlog entirely, according to a study by the Congressional Research Service.

Those who receive a “notice to appear” in immigration court can be scheduled for court dates years into the future. 

Using a tool developed by Kerwin and his son, independent researcher Brendan Kerwin, CBS News estimated that the backlog of immigration cases would be 13.5 million by FY 2028 if the courts received 11 million new cases. 

The tool takes into account the rate at which immigration judges process cases, the number of new cases each year, and the number of judges hired. The Executive Office of Immigration Review, which oversees immigration courts, planned for 150 new judges in the 2024 fiscal year. If the government hired 150 new judges each year for the next four years, sending 11 million undocumented immigrants notices to appear would leave the courts with a 13.5 million case backlog by FY 2028. 

Trump could take steps to eliminate that legal process for some immigrants, which could lead to a smaller backlog. Under a 1996 law, those who were apprehended within 100 miles of the border within two weeks of their illegal crossing could be deported without a court hearing. The Trump administration previously expanded that law to apply to the entire country and any undocumented immigrants who entered illegally and had been living in the U.S. for less than two years. 

Mass deportations would reduce jobs

Beyond the costs outlined above, deporting millions of migrants could also negatively impact the U.S. economy and job market. 

One study found that Obama’s Secure Communities program, which deported nearly half a million undocumented immigrants, not only pulled those immigrants from the workforce but had a ripple effect of decreasing the employment and hourly wages of U.S.-born people as well. Scaling their findings, the researchers estimated that for every 1 million unauthorized workers deported, 88,000 native-born jobs would be lost. 

An analysis from the nonpartisan Peterson Institute for International Economics released last month reached similar conclusions. Researchers found that a mass deportation of even just 1.3 million undocumented immigrants would lower GDP and reduce employment in the U.S. by 0.8% by 2028. A larger mass deportation of over 8 million immigrants would have a larger effect, lowering employment to 5.1% below the current baseline.  

Undocumented immigrants also paid $59.4 billion in federal taxes and $37.3 billion to state and local taxes, according to a study by the Institute on Taxation and Economic Policy. More than a third of those went to Medicaid, Social Security and unemployment insurance. 

Over 4 million families could be separated

Mass deportation would not only reduce jobs for citizens, but impact family members who are citizens. There are roughly 4.1 million mixed-status families living in the U.S., according to data from the Pew Research Center. About 4.4 million U.S.-born children live with an undocumented parent.

Children whose parents are deported “often leave school, they end up with trauma, mental health challenges, behavioral problems,” said Andrews, the U.C. San Diego researcher. “Spouses often have to deal with not only the incredible emotional cost of having their partner deported but also with the economic cost of having to relocate or having to take on another job.”

And the immigrants facing deportation, Andrews said, “end up extremely disoriented and in an existential limbo.”

“The economic cost will be extremely high, but the social, emotional, and community costs will also be extraordinarily high,” she added.