In his 2024 presidential campaign, Donald Trump is promising to deport millions of migrants now living in the U.S. if he is elected. While his followers wave signs reading “Mass Deportation Now!” and polling shows that support for the policy has increased, what’s missing from the conversation is the often-brutal reality of what mass deportations have looked like in America’s past — and what they might look like in the near future.

Many historians of immigration see America’s previous experiments in mass deportation as failures, both because they did not accomplish their purported goals and had widespread negative social effects. Similarly, many policy analysts predict that any mass deportation plan attempted by a second Trump administration would be shambolic and likely stuck in a legal and logistical quagmire. Others, however, suggest we should not underestimate the willingness of Trump and his 2024 inner circle to violate legal and political norms and bulldoze the kinds of obstacles that might stop a more conventional administration.

There have been several attempts to deport large numbers of immigrants throughout American history, but the largest — and the one Trump has previously referenced — was literally called Operation Wetback, using a blatantly offensive term for immigrants from Mexico who had allegedly entered the U.S. by wading or swimming across the Rio Grande.

That operation, which began in June 1954 and was largely managed by retired U.S. Army Gen. Joseph Swing, then the head of the Immigration and Naturalization Service, saw the federal government deploy military-style tactics to round up migrants, mostly in the Southwest and major West Coast cities, and deport them.

Exactly how many people were deported during the 1954 operations is unclear. The INS reported that apprehending about 1.1 million people, while other estimates suggest that as many as 1.5 million people were deported. While the goal was to focus on undocumented immigrants, there is clear evidence that some U.S. citizens and legal residents were also swept up in the operation and deported. Trump promises to go beyond these numbers.

“Impossible Subjects,” a 2014 book by Columbia University historian Mae Ngai, details the history of Operation Wetback from the circumstances that led to the Eisenhower administration to pursue the policy, through the operation to its ultimate conclusion.

During the early 1950s, backlash against migration across the southern border began to build, in terms that seem strikingly familiar today. In 1951, President Harry Truman’s Commission on Migratory Labor described the influx of Mexican immigrants as “virtually an invasion.” Agricultural interests in California and the Southwest, however, largely depended on transient labor in order to pick and process vegetables.

Ngai notes that proponents of the INS operation often spoke of migrants in demeaning terms. Gen. Swing said that “hordes of aliens” were crossing the Mexican border, calling it an “alarming, ever-increasing, flood tide.” of migrants at the border. A Los Angeles Times story from 1955 quotes a U.S. government official calling Mexican immigration “history’s greatest peacetime invasion.”

Perhaps surprisingly, there was also significant support for tightening immigration policies among some Latino and Hispanic groups in the U.S. including the League of United Latin American Citizens. That stemmed from the perception among Mexican Americans that “braceros,” a term used to describe temporary agricultural workers from Mexico, were depressing wages for U.S. citizens.

In “Walls and Mirrors,” his study of Mexican-American immigration, historian David G. Gutiérrez quotes one Mexican American at the time saying, “I still don’t know if I’m for or against the braceros” but adding, “I also know that when the braceros come in, the wages stay very low.” 

Gutiérrez writes that support for deportations began to drop among Mexican Americans, however, as they came to realize that INS “dragnets not only were affecting putative illegal aliens but also were devastating Mexican American families, disrupting businesses in Mexican neighborhoods, and fanning interethnic animosities throughout the border region.”

In her book, Ngai writes that Operation Wetback was at best “a short-term success” for its proponents. Some previously undocumented migrants acquired work contracts through the bracero program, which allowed for Mexican citizens to work legally in the U.S. between 1942 and 1964. Furthermore, unofficial or extralegal migration continued throughout the program and many of those deported to Mexico during the operation later returned to the U.S.

In an email, Ngai described Operation Wetback as little more than “a short-lived propaganda effort" that failed to prevent unauthorized border crossings and also inflicted a significant human cost on both migrants and American citizens. 

One U.S. labor official, according to Ngai, reported that 88 deportees died of heat exhaustion or sunstroke in July of 1955 after being dropped off in the border city of Mexicali in 112°F July heat. A congressional investigation into the program likened one boat used to transport deportees to an “18th-century slave ship.”

Another Los Angeles Times report on a roundup of immigrants begins by noting, “Human misery was compounded here today by a blistering desert sun and swirls of alkali dust.” The same article recounts a group of migrants promising to return, some as legal bracero program workers and others as unauthorized workers, indicating that this “human misery” had likely accomplished nothing. “One band of four bound for Guadalajara offered to visit a reporter at his Los Angeles home within three weeks,” the article concludes.

Well over a million people were deported during the 1950s, and there’s no doubt that U.S. officials could deport millions more under a second Trump administration. But Ngai is skeptical that Trump could make good on his “threat” to launch the largest deportation campaign in American history.

By most estimates, there are around 11 million undocumented migrants in the U.S., dramatically lower than the 15 to 20 million that Trump has vowed to deport. The other problem, as Ngai said email, is that the federal government simply "does not have the capacity to round up 10 million people.”

For one thing, even an aggressive Trump administration could likely find no way to coerce states like California, New York and Illinois — Democratic-dominated states with large immigrant populations — to play along with a mass deportation plan.

“What is he going to do — go house to house and raid workplaces?" Ngai asked. "Maybe in a few places as a show of force" that would work, she said, but it's "not possible throughout the country. Will Americans stand by and let this happen?”

Former INS commissioner Doris Meissner, in an interview with Salon, noted similar issues that a second Trump administration would face, citing three problematic categories.

“The first has to do with the practical application of resources and the wherewithal to do it," Meissner said. "The second has to do with could it actually work. The third concerns the broader implications of doing significantly increased deportation.” 

Meissner said that the agency primarily responsible for deportations, Immigration and Customs Enforcement or ICE, simply lacks the resources required to conduct deportations at the scale Trump is discussing. Congress would probably need to approve dramatically increased funding, which would only happen if Republicans control the House, the Senate and the presidency in 2025. Although Trump has mentioned deputizing National Guard troops or local law enforcement to pursue deportations, that would also present enormous logistical challenges.

Secondarily, there is the issue of actually locating people who are potentially eligible for deportation. Typically, undocumented immigrants enter the deportation system after an unrelated encounter with law enforcement. During the Trump administration, ICE priorities were shifted from targeting those who had committed a serious crime to a definition so broad enough it could include almost any undocumented migrant.

As mentioned above, roughly 11 million of the 47 million or so foreign-born residents of the U.S. are believed to be unauthorized. Many live in large cities or states governed by Democrats, and many already enjoy some sort of protected status, even if they entered the country illegally. Roughly 500,000 are the spouses of U.S. citizens, and close to 900,000 (including the Haitian immigrants in Ohio demonized by Republicans) hold Temporary Protected Status and cannot legally be deported. At least another 500,000 fall under the Deferred Action for Childhood Arrivals program (aka the "Dreamers") and another 530,000 people are part of a parole program, according to the Migration Policy Institute, where Meissner serves as a senior fellow.

A large proportion of unauthorized U.S. residents live in mixed households, meaning that other members of the household are U.S. citizens or legal residents. Any efforts at mass deportation in this context would certainly mean separating families, a policy that created major controversy and blowback during the first Trump administration. Law enforcement would need training in identifying who is or is not eligible for deportation, and would likely have to go door to door in hostile communities in hopes of finding the millions Trump hopes to expel.

Then would come the potentially horrifying issue of establishing holding facilities for potential deportees after they are rounded up. Meissner said that military bases would be the likely candidates, which could create tensions between the Department of Defense and the White House. The many new laws or regulations established to carry out mass deportations would almost certainly end up in court, which might not shut down the program but would likely delay or disrupt it.

The Trump administration would also need cooperation from the countries to which it intends to deport migrants, which could require extensive diplomatic efforts. Although an estimated 45 percent of undocumented immigrants living in the U.S. are originally from Mexico, the others come from many other nations in Latin America, the Caribbean and all around the world. 

Finally, Meissner questions how a mass deportation program would affect American society. Not only would families be torn apart, neighborhoods emptied out and industries disrupted, such program would create “a climate of fear,” she said. 

Even if a second Trump administration succeeds in deporting an increasing number of immigrants, Meissner continued, “the larger outcome will be fear in immigrant and migrant communities and significant antipathy among Americans in general.” 

Patrick Eddington, a senior policy analyst for national security and civil liberties at the libertarian-leaning Cato Institute, takes a darker view, arguing that it's "naive" to suggest that Trump would be deterred by logistical complications. He suggested in an interview that Trump might declare the presence of undocumented migrants a threat to national security and use the broad powers afforded to the president to carry out deportations, adding that the federal judiciary has historically deferred to the executive branch on issues of national security. 

Eddington pointed to Trump’s 2017 Muslim ban as an example. That attempt to bar entry to immigrants or travelers from many Muslim-majority nations was initially blocked by the courts. But after the Trump administration reworded the ban's language and expanded the list of affected countries to include North Korea and Venezuela, it was allowed to go into effect.

Eddington agreed that Democratic-led states like California would probably offer resistance to mass deportations, he identified Democratic control of at least one chamber of Congress as the best way to prevent such a program from happening. Even in that scenario, he said that Republicans could seek to tie funding for deportations to must-pass government funding bills. 

“In terms of coming up with the manpower and the money, that’s not the obstacle and it wasn’t the obstacle 70 years ago,” Eddington said. “If the Republicans are able to take over the House and the Senate, they will cut Trump whatever checks he wants to do this program.”

Even if the federal courts were to challenge Trump’s authority, Eddington points to Andrew Jackson’s defiance of the Supreme Court on the removal of Native Americans from their lands as an important precedent. The Supreme Court’s recent decision on presidential immunity would surely further empower Trump in this respect, and Trump could potentially issue blanket pardons for those carrying out his orders, even if those orders are found to be illegal.

Many people, Eddington said, are underestimating the willingness of those people now in Trump's orbit to pull the levers of power. He cited former Defense Secretary Mark Esper as an example of the sort of moderating force during the first Trump administration who would not be present the second time around. 

---

Want a daily wrap-up of all the news and commentary Salon has to offer? Subscribe to our morning newsletter, Crash Course.

---

In his 2022 memoir, “A Sacred Oath,” Esper disclosed that Trump had suggested that law enforcement should shoot protesters near the White House following the police murder of George Floyd. Esper writes that he had to “figure out a way to walk Trump back without creating the mess I was trying to avoid.” 

Trump’s family separation policy also serves, Eddington said, as an instructive example of what a potential Trump administration might be willing to inflict, not just on new arrivals but also on people who have been living in the U.S. for years. In 2017, the Trump administration began deliberately separating children from their families at the border, in an attempt to deter people from crossing and with no plan in place to reunite separated families. In the final report on family separation, issued in 2021. there were still 1,703 children who had not been reunified with their families. According to the National Immigrant Justice Center, family separation has continued into the Biden administration, if on a smaller scale.

Many observers, Eddington said, are “underestimating Trump and they’re underestimating the people surrounding him now. They’re underestimating how far those people are willing to go. People underestimate the prospects of peril not just to people who are here illegally but, from what we know from the past, to American citizens.”