Trump has repeatedly floated the idea of sending U.S. citizens convicted of crimes to prisons in El Salvador, but experts question how realistic that is.

President Donald Trump has repeatedly raised the idea of sending U.S. citizens who have been convicted of some crimes to prisons in other countries.

On Sunday, the president told reporters on Air Force One that “we have some horrible criminals, American grown, born,” and that he’s “all for” sending them to prisons in El Salvador — where some Venezuelan migrants are already being detained. “I don’t know what the law says on that,” he said.

White House press secretary Karoline Leavitt defended the comments Tuesday, telling reporters that in reference “to the president’s idea for American citizens to potentially be deported, these would be heinous, violent criminals who have broken our nation’s laws repeatedly.”

While immigration experts say there is no legal way for a person with U.S. citizenship to be deported, Supreme Court Justice Sonia Sotomayor sounded a warning this month about the Trump administration’s stance on the matter in a dissenting opinion that referenced a case regarding the mistaken deportation of a Salvadoran immigrant in Maryland.

“The implication of the Government’s position is that not only noncitizens but also United States citizens could be taken off the streets, forced onto planes, and confined to foreign prisons with no opportunity for redress if judicial review is denied unlawfully before removal,” she wrote.

Here’s what to know.

What has the Trump administration said about sending U.S. citizens to foreign prisons?

In February, Secretary of State Marco Rubio said he was “incredibly grateful” for Salvadoran President Nayib Bukele’s offer “to house in his jail dangerous American criminals in custody in our country, including those of U.S. citizenship and legal residents.”

State Department spokeswoman Tammy Bruce called it an “extraordinary gesture never before extended by any country.”

Last month, after attacks on Tesla dealerships and vehicles in protest of Trump’s influential adviser Elon Musk, Trump said on social media that he hoped offenders would “get 20 year jail sentences” that could be served “in the prisons of El Salvador.”

Gabriel J. Chin, a professor and scholar of immigration law at the University of California at Davis, said in an email that such a proposal is “the equivalent of sending political opponents to the Gulag in the Soviet Union era.”

El Salvador’s prisons have been decried by human rights groups and the U.S. government itself, which described “harsh and life-threatening prison conditions” in a 2023 report, including allegations of arbitrary or unlawful killings from medical neglect or physical abuse.

Is it legal to deport a U.S. citizen?

No, a U.S. citizen cannot legally be deported or denied entry to the United States. Jean Reisz, an associate professor of law who co-directs the University of Southern California Gould School of Law Immigration Clinic, said Trump’s suggestion “does not seem very realistic.”

U.S. citizens who have gone overseas to fight for terrorist organizations such as the Islamic State must be allowed to return, she said. The government “can detain them. They can charge them with crimes and incarcerate them if they’ve been convicted of certain crimes, but they can’t be denied entrance back into the U.S.”

In addition to voicing those concerns, Chin pointed out that “there are serious arguments that it is illegal, in the sense of not being an authorized punishment under law, and unconstitutional under the Eighth Amendment as a cruel and unusual punishment” to send incarcerated U.S. citizens to Salvadoran prisons.

Only former U.S. citizens who have lost their citizenship can be deported.

How can a U.S. citizen lose citizenship?

The clearest way to lose citizenship is to voluntarily renounce it. Beyond that, there are only a few ways a person can be expatriated or denaturalized.

For a U.S.-born citizen, the government would have to prove that the person had committed some act with the intent of giving up their citizenship — such as serving in a foreign military, running in a foreign election or committing treason.

Intention is crucial because such actions alone cannot deprive a person of citizenship, Reisz said, adding: “The government could maybe prove intent through circumstantial evidence, but it’s very hard to do.”

For naturalized citizens, there is an additional way — if the government proves they were not entitled to citizenship in the first place, such as if they obtained it through some sort of fraud. A legally naturalized citizen who is convicted of an unrelated crime later cannot be stripped of their citizenship for that crime.

“Citizenship is more than just something that the government can give and revoke,” Reisz said. “It’s an entitlement; it’s a right.”