Two former officials who handled immigration issues for then-President Donald Trump have stated that a "whole of government" approach, costing billions of dollars, would be necessary to implement the "largest deportation effort in American history" as promised in the Republican convention platform if Trump is re-elected. This effort would require extensive coordination and resources from various federal agencies and departments to deport millions of undocumented immigrants.

The exact number of people who would be deported under a second Trump administration remains uncertain. During a presidential debate on June 29, Trump claimed there were 18 million undocumented immigrants in the United States, while one of the former officials suggested the number could be as high as 30 million. However, the most recent government estimate indicates that just under 11 million unauthorized immigrants resided in the U.S. as of January 1, 2022. This number represents an increase of 500,000 from two years earlier but is a decrease from the 2010 total of 11.6 million. It remains unclear how many more noncitizens have entered the U.S., changed their legal status, or left voluntarily since that estimate.

Regardless of the current total of undocumented immigrants, deportation efforts during both the Trump and Biden administrations have been minimal compared to what the Republican National Convention platform promises for a second Trump presidency. During Trump's years in office, there were approximately 935,089 deportations, according to Immigration and Customs Enforcement (ICE) data. As of February, there have been an estimated 339,751 deportations during the Biden administration.

Last week, former acting ICE Director under Trump, Tom Homan, who is seen as a potential Department of Homeland Security chief in a second Trump administration, told a conservative conference, “They ain’t seen s--- yet. Wait until 2025.” He added, “Trump comes back in January. I’ll be on his heels coming back, and I will run the biggest deportation force this country has ever seen.”

In a statement, Trump campaign national press secretary Karoline Leavitt said, "A majority of Americans want mass deportations for illegal immigrants. On Day One back in the White House, President Trump will begin the largest criminal deportation operation of illegal immigrants and restore the rule of law.”

NBC News interviewed acting ICE Director Patrick J. Lechleitner about the requirements to deport millions of people. While he did not comment specifically on the Republican convention platform, he highlighted the complexity and logistical challenges of such a massive deportation effort. Lechleitner explained, “It’s not only putting them on planes and flying them, which is expensive; we got to have airplanes. We also have to deal with host nations. We have to get travel documents, we have to do all the logistics involved with that.” He noted that for some individuals not in detention, the deportation process can take years, requiring continuous monitoring, which is resource-intensive.

Abigail Andrews, a professor of urban studies and planning at the University of California, San Diego, who has been studying deportation data for the past 10 years, expressed skepticism about the feasibility of a mass deportation effort. “There is no logistical way to track down 10 to 12 million undocumented immigrants with the ICE employees they currently have,” she said. She pointed out that most deportees are not arrested in their homes by ICE agents but end up in ICE custody following interactions with local law enforcement, such as traffic stops. Andrews also noted that research shows immigrants commit fewer crimes than average Americans.

Ammon Blair, a former Border Patrol agent who left the agency in 2023 and is now a senior fellow at the Texas Public Policy Foundation, also doubted the practicality of such an effort. "I honestly just don’t see it happening," he said. "One, because I think it’s political suicide, and two, I think we need to focus on national security issues." Blair emphasized that an operation of this magnitude would require significant involvement from local law enforcement, which are already handling substantial responsibilities. He highlighted the lack of manpower and resources to handle such an extensive operation and warned that the optics of deporting children could create significant backlash.

Mark Morgan, former acting commissioner of Customs and Border Protection under Trump, suggested that mass deportations should prioritize individuals who have committed serious crimes rather than targeting families. He proposed additional funding to ICE and consequences for cities that refuse to cooperate with federal immigration enforcement. “One thing I think we need to do is go after the sanctuary cities to take away their funding,” said Morgan, who is now a visiting fellow at the Heritage Foundation, a conservative think tank.

Experts have pointed out that the costs associated with an operation of this size would be substantial. The ICE budget for transportation and deportation in 2023 was $420 million, during which the agency deported 142,580 people. Deportation costs vary widely depending on the destination country and include variables such as commercial flight costs, security needs, and the use of charter flights. The removal of 10 million people could easily run into tens of billions of dollars. Additionally, the millions of deportees would need to be detained and housed prior to removal. Currently, ICE manages 41,500 beds across 200 jails and detention centers at a cost of $57,378 per year per bed, according to public budget documents. In the event of a mass deportation, the government would need to fund significantly more beds. Andrews commented, “The combined cost would be astronomical.”

Supporters of mass deportation argue that the cost of detaining and removing undocumented immigrants is justified due to the significant cost savings associated with reduced education and healthcare spending on undocumented communities. However, families with mixed status, such as those with children who are U.S. citizens and parents who are undocumented, present additional challenges. One former Trump official suggested that the threat of deportation for one family member could prompt entire families to leave voluntarily. “Your parents can’t use you as a prop to justify their illegal presence,” the former official said.

The former Trump officials emphasized that a "whole of government" approach would be essential to implement such a large-scale deportation effort. One ex-official mentioned the need for a "trigger puller" at the Department of Homeland Security (DHS), someone willing to defend the deportation initiative before Congress. They outlined the necessity for cooperation and resources from agencies such as the Pentagon, which could be asked to set up detention camps or relocate migrants to foreign military bases. The Interior Department might be involved in providing federal land for deportation sites. Additionally, the Justice Department, the Drug Enforcement Administration, and the Department of Health and Human Services, which oversees the care and custody of unaccompanied children, would also need to contribute to the effort.

Mario Russell, executive director of the Center for Migration Studies, a think tank that advocates for immigrant rights, agreed that deporting millions of people would require comprehensive government involvement but criticized the proposal as "folly and absurdly expensive and counterproductive, not to mention profoundly cruel." Russell's team estimates that about 50% of the nation's undocumented population consists of individuals who overstayed their visas. He noted that others might have "Dreamer" status, temporary worker status, or are navigating the asylum process. Russell recalled that his group prepared for a similar mass deportation scenario before Trump’s inauguration in 2017, but no large-scale removal materialized. "One is left to wonder if it’s more talk than threat," he said.

The proposal for mass deportation by a potential second Trump administration continues to stir significant debate and concern. The logistical, financial, and ethical challenges of such an endeavor underscore the complexity of immigration enforcement and the profound impact it could have on millions of individuals and families across the United States.