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At a campaign rally in the border state of Arizona on Thursday, Donald Trump fired up the crowd with a promise to undertake the largest mass deportation in US historyafter lamenting that the country had become “like a dustbin for the world”.

That promise to round up and deport the estimated 11 million U.S. immigrants who lack permanent legal status is one of Trump’s 2024 campaign promises and one of his biggest cheers. Trump has privately concerned that the stump speeches focused on less divisive topics — says the economy — leaves its audience bored, the New York Times reported this week.

More recent media analysis they found that a second Trump administration would face myriad challenges in affecting mass deportations on this scale, and that the effort would require a Herculean attitude. reworking every aspect of the criminal justice and immigration detention systems.

A study by the American Immigration Council, a pro-immigration advocacy group, calculated that the deportation effort would require hundreds of new detention centersand hundreds of thousands of new immigration officers, judges and other staff. Fiscal analyzes concluded that mass deportation on this scale could it cost hundreds of billions of dollars. Even at the current rate of enforcement, detention and deportation, Immigration and Customs Enforcement is already hindered in its “ability to maintain a safe and secure environment for staff and inmates,” at its facilities, according to a Department of Homeland Security report released last month. Many of these detention facilities are run by private companies in former prisons. Bloomberg News reports this week that Trump’s deportation plan it could mean a huge financial opportunity for operators like CoreCivic and GEO Group.

To circumvent the already lagging deportation system, Trump and his aides said that intends to invoke the Alien Enemies Act of 1798. The law — which was used during two world wars — allows the president to arrest, detain or deport immigrants from a country deemed a wartime enemy of the US without due process. Its use would attract immediate legal challenges, and legal experts are divided on how such an effort would fare in the courts. The US is not at war with any of the countries from which large numbers of migrants arrive, which is what the language of the act requires. However, courts are often deferential to the executive branch regarding this type of authority.

Enforcement efforts would likely include the use of new surveillance technology. Some technology watchers you worry about an increase in technology that is already becoming ubiquitous at the border, including surveillance towers, high-tech blimps, incognito license plate readers and biometric readers.

Trump has also repeatedly said that he plans to mobilize local law enforcement carry out elements of his deportation agenda as well as the National Guard in states where the governor is sympathetic to that goal.

Some law enforcement leaders have already stated that they will not participate in mass deportation efforts. Even officials who have expressed concern about the challenges created by large influxes of migrants are not necessarily keen on mass deportation. In Whitewater, Wis., Police Chief Dan Meyer told ProPublica he was irritated through efforts to politicize the situation in his city, where at least 1,000 migrants, mostly from Nicaragua, have recently settled.

Meyer said his department faced “very real challenges with so many people arriving from another country,” mainly related to poverty, language barriers and administrative challenges — such as the fact that many migrants do not have and struggle to to obtain driver’s licenses.

But what Meyer said was not happening was a siphoning migrant crimea claim that has been a cornerstone of Trump’s mass deportation campaign. Meyer told ProPublica that new immigrants do not commit crimes at a higher rate than other Whitewater residents.

In Aurora, Colorado, another police chief says Trump’s claims don’t represent the reality on the ground. Chief Todd Chamberlain told NBC News earlier this month that the city is very safedespite Trump describing her as “outgunned” by members of the Venezuelan Tren De Aragua (TDA) gang. Trump identified Aurora as the epicenter of his deportation efforts.

Chamberlain said there are crimes linked to TDA members, but that Trump’s rhetoric has dramatically overstated the situation. This week, NBC News reported that the Department of Homeland Security has identified approximately 600 migrants from across the US who may have links to TDAalthough some quoted experts said this number was definitely an undercount.

Beyond the legal and logistical challenges of Trump’s deportation plan lie profound potential economic costs. “It would certainly cause unrest and unrest,” an Arkansas business leader told the New York Times, referring to the labor force that migrants provide in fields that are either unattractive to American workers or where there are acute lack of native labor force. Some analyzes suggest that a complete mass deportation could reduce the output of more than a trillion dollars in the US economy and causing a contraction similar to the Great Recession of 2009.

None of this explains the human toll of mass deportations. Writing for Texas Monthly, Jack Herrera tells the story of Marco, a Honduran man from Georgia who works in construction and landscaping. Marco had been deported once before, in 2010, and had planned to make peace with life in Honduras. But the threat of violence from local gangs there and the prospect of earning 10 times the annual income, lured him back to the US in 2021.

Like most undocumented people in the US, Marco lives in a mixed-status home, meaning “some relatives have citizenship or green cards, and some don’t.” If Marco were deported, Herrera writes, “It’s his family who would really miss him—the girls waiting for their uncle to come home every sunset with mud on their boots and wood chips on their shirts.”