As a presidential candidate, Gov. Ron DeSantis of Florida has said he would authorize the use of deadly force against people crossing the border, seek to end the practice of birthright citizenship and send the military to strike against drug cartels inside Mexico, a key ally of the United States, even without the permission of its government.
Those positions put him on the hard right among the Republicans running for president, many of whom are tapping into deep anger among G.O.P. primary voters over immigration.
Now, Mr. DeSantis, who often tries to stoke outrage with his border policies, has unveiled another extreme position: deporting all undocumented immigrants who crossed the border during the Biden administration.
“Everyone that has come illegally under Biden” should be sent back, Mr. DeSantis said on Friday in response to a reporter’s question at a campaign event in Long Beach, Calif. “That’s probably six or seven million people right there. It’s going to require a lot of effort. It’s going to require us to lean in.”
Though Mr. DeSantis greatly overestimated the number of people who have entered the country illegally since Mr. Biden took office, such mass deportations would require enormous investments in the nation’s immigration enforcement system and could do severe economic harm to key American industries.
Conducting so many deportations would require Mr. DeSantis to hire more Immigration and Customs Enforcement officers, authorize widespread raids into immigrant communities, significantly expand immigration detention space to meet national standards and substantially grow the fleet of airplanes used for deportations. Billions more dollars would need to be spent on bolstering immigration courts to adjudicate cases within months instead of years. Currently, some migrants who have recently arrived in the United States have been given court dates a decade from now because the immigration court backlog is so large.
Still, Mr. DeSantis is not alone in his promises to upend the nation’s immigration system.
On Friday, former President Donald J. Trump, who is leading the Florida governor by roughly 40 points in national polls, pledged to enact “the largest deportation operation in the history of our country” if re-elected. Mr. Trump was speaking at the same time as Mr. DeSantis, roughly 20 miles away at a convention of Republican activists in Anaheim, Calif.
The dueling speeches highlighted how crucial an issue border security has become in the Republican presidential primary. At his campaign event, Mr. DeSantis took the opportunity to criticize Mr. Trump, saying that his rival had failed to “get the job done” on the border during his first term. Though the two men are largely aligned on immigration policy, Mr. DeSantis is making the argument that he would be more effective in carrying out a hard-line vision.
“I would note that the former president is campaigning on the same promise he made in ’16 that he didn’t deliver on,” Mr. DeSantis said.
With his “six or seven” million figure, Mr. DeSantis was probably referring to the roughly six million people who have been caught crossing the border since 2021. That is about double the number of unauthorized immigrants who actually entered the country under Mr. Biden and are still here.
Of those six million, at least 1.6 million have been allowed to stay in the country temporarily and face charges in immigration court. Officials estimate about 1.5 million others have entered the country illegally without being detained.
The government estimates about 11 million undocumented people live in the country overall.
Mass deportations are not as simple as the Republican contenders make them sound.
Many of the people they call illegal immigrants are eligible for legal status in the United States or are already here on a legal status. An example of a legal status is Temporary Protected Status, the humanitarian benefit Mr. Biden just extended to nearly 500,000 Venezuelans who have come to the country since the spring of 2021. People who are in the country and eligible for legal status are entitled to a hearing before an immigration judge, said Greg Chen, the senior director of government relations for the American Immigration Lawyers Association.
The time it would take to remove millions of people is substantial. In the past, the greatest number of deportations has been around 400,000 a year. The year with the highest number in recent history is 2013, during the Obama administration, when there were more than 432,000. During the Trump administration, the year that saw the most deportations was 2019, with more than 359,000.
“DeSantis’s statement demonstrates his utter lack of any understanding of immigration enforcement operations,” Mr. Chen said. “At a practical level, deporting that many people would be impossible in even a single term.”
Mr. Chen also pointed out the serious economic costs of deporting many of the workers who take on the United States’ most dangerous and low-paying jobs, particularly in agriculture.
Immigration laws signed by Mr. DeSantis in Florida this year have already led to worker shortages in the agricultural sector, as well as in construction and hospitality, some employers have said. In addition, undocumented workers play a key role in hurricane cleanup in the state, but many have said they would no longer risk traveling to Florida because of the threat of deportation.
There is also a significant diplomatic component to deportations — countries must be willing to take back their citizens, and the United States must have relations with those countries to coordinate those return trips. This stipulation would pose a huge challenge in returning the hundreds of thousands of Venezuelans who have fled to the United States in the past few years. A DeSantis or Trump administration would most likely need to reestablish diplomatic relations with Venezuela and recognize the government of Nicolás Maduro — something Mr. Trump did not do as president — to carry out their plans.
“Mass deportations are really, really, really hard to do,” said Aaron Reichlin-Melnick, the policy director at the American Immigration Council, a pro-immigrant organization. “The political backlash would be enormous.”
Ron Vitiello, a former acting director of ICE during the Trump administration, acknowledged that there were “logistical, practical and legal challenges” to deporting so many people. But he said that immigrants would continue to cross the border illegally if they believed that they would be able to stay long-term.
“If the rest of the world believes they’ll never be deported, that is an incentive for lots of people,” Mr. Vitiello said. “You have to end the incentives to change the traffic patterns at the border.”
When Republicans tried to enact comprehensive immigration reform under President George W. Bush, the idea of deporting large numbers of undocumented people was not considered realistic or desirable, reflecting how deeply the political mood in the G.O.P. has shifted in the years since.
“Mass deportation is not a workable solution,” the Bush administration argued in a 2007 fact sheet, at a time when the population of unauthorized immigrants was even higher than it is today. “Deporting the millions of illegal immigrants who are already in the country would be impractical, harmful to our economy, and potentially devastating to families with deep roots in their communities.”
Jonathan Swan contributed reporting from Long Beach, Calif.