Trump is invoking the Alien Enemies Act. Here are answers to key questions about the 1798 law

Customs and Border Patrol agents load migrants into a vehicle after groups of migrants walked into the US from Mexico at Jacumba Hot Springs, California, on June 5, 2024. (Frederic J. Brown/AFP/Getty Images via CNN Newsource)

U.S. President Donald Trump has issued a proclamation invoking the Alien Enemies Act, an 18th-century law previously used when the US was at war.

The law has been invoked three times before — most recently as a justification for some internments during World War II.

This time, Trump says he’s targeting Venezuela’s Tren de Aragua gang, declaring that its members “have unlawfully infiltrated the United States and are conducting irregular warfare and undertaking hostile actions against the United States.”

The move to invoke the 1798 law is already facing a legal challenge. A federal judge said Saturday that he was temporarily blocking the administration from conducting deportations under the Alien Enemies Act. But Secretary of State Marco Rubio said Sunday that more than 250 Tren de Aragua members had been transported to El Salvador after Trump’s proclamation.

Here’s a look at some key questions and answers about the Alien Enemies Act:

What circumstances allow the president to invoke this law?

The text of the Alien Enemies Act says it can be invoked whenever:

A war is declared between the US and “any foreign nation or government” OR

“Invasion or predatory incursion is perpetrated, attempted, or threatened against the territory of the United States by any foreign nation or government” AND

“the President makes public proclamation of the event”

In other words, if the US is at war with another country, or a foreign nation or government has invaded the US or threatened to, a president can invoke the Alien Enemies Act.

But the US isn’t at war with any other nations. Can this law still apply?

In his proclamation invoking the act, Trump states that Tren de Aragua, which his administration has also designated a foreign terrorist organization, “is perpetrating, attempting, and threatening an invasion or predatory incursion against the territory of the United States.” The proclamation also asserts that this is occurring “directly and at the direction, clandestine or otherwise, of the Maduro regime in Venezuela.”

A lawsuit filed Saturday by the American Civil Liberties Union and Democracy Forward disputes that claim.

“Tren de Aragua, a criminal organization, is not a nation or foreign government and is not part of the Venezuelan government, (nor) does it receive support from the government,” the lawsuit says, arguing that the US “cannot declare war against Tren de Aragua because it is not a nation. And neither Venezuela nor Tren de Aragua have invaded or threatened to invade the United States.”

Why would Trump invoke this law rather than turning to the laws typically used for immigration enforcement?

Trump said in October that he wants to use the 1798 law because “it gives tremendous authority to everybody to straighten out our country.”

“You have to go back that far, because as we’ve grown and grown, our politics and politicians have become weaker and weaker,” he said at an October rally in New Mexico. “Our laws don’t mean anything.”

Detentions and deportations that occur under the Alien Enemies Act do not go through the immigration court system, which provides immigrants the chance to seek relief and make their case to stay in the country. Experts have noted that the backlogged court system, where cases can take years, could be a significant obstacle to Trump’s mass deportation plans.

“So that’s where I think the Alien Enemies Act comes in,” Jean Lantz Reisz, co-director of the immigration clinic at the University of Southern California’s Gould School of Law, told CNN last year. “I think that Trump is citing this as a way to kind of bypass all of that due process and make it easier to arrest and deport people.”

Katherine Yon Ebright of the Brennan Center at New York University also said the president was using the Alien Enemies Act to dispense with due process. “He wants to bypass any need to provide evidence or to convince a judge that someone is actually a gang member before deporting them,” she said in a news release.

Does focusing on those groups change things?

“A cartel member, a gang member isn’t going to be a foreign government,” USC’s Reisz said. “If the Trump administration … wanted to designate (a cartel) as a foreign government, that would run into problems, because there can only be one government of a nation.”

George Fishman, a former Department of Homeland Security deputy general counsel in the first Trump administration, authored an analysis in 2023 arguing the 18th-century law “needs to come out of retirement” and should be considered “a valuable war-fighting tool during future conflicts.”

But Fishman told CNN last year he thinks the law couldn’t be used for a general deportation plan targeting undocumented immigrants.

“I think that wouldn’t stand up in federal court, because I don’t think their actions can be attributed to those governments. And even if they could, then the question comes up of whether mass illegal immigration constitutes an invasion,” he said. “That argument has been made … but no federal court has yet accepted it. So that would be another hurdle.”

Overcoming these hurdles would be an “uphill climb in federal court,” Fishman argued in the analysis he wrote for the Center for Immigration Studies. Fishman is a senior legal fellow at the think tank, which supports curbing immigration to the U.S.

But it’s possible, he says, that officials could try to make the case that certain nations are effectively “mafia states” where organized crime has infiltrated the government.

“I think a very strong argument could be made that in those situations, the Alien Enemies Act can be employed,” he says. “But, you know, it would be a case-by-case situation.”

Why was this law created?

French nationals were the original target lawmakers had in mind when they passed the Alien Enemies Act.

“It was informed by the French Revolution … It was aimed at quashing political opposition from immigrants who were sympathetic to France,” said Mae Ngai, a history professor at Columbia University.

At the time, lawmakers thought giving the president broad authority to detain and deport enemies made sense, according to the Brennan Center’s Ebright.

“We were in this undeclared naval conflict with France, and the Congress was very worried that naval conflict could escalate into another major ground war with a European power, and…we have none of these tools for prosecuting espionage (or) sabotage, for trying to take people who are maybe trying to injure the national security and removing them from the country. None of that exists,” Ebright told CNN last year.

Other laws passed at the time — collectively known as the Alien and Sedition Acts — expired a few years later, Ngai says, but the Alien Enemies Act had no expiration date and remains on the books.

When has the Alien Enemies Act been used before?

The law has been invoked three times before — always in connection with a declared war: during the War of 1812, during World War I and — most recently — as a justification for the internment of German, Italian and Japanese nationals during World War II.

“It wasn’t a blanket roundup, but they investigated people, and they had the authority to detain them for the period of the war,” Ngai said.

Detentions connected with the Alien Enemies Act were separate from the internment of more than 100,000 Japanese Americans that occurred as a result of an executive order from President Franklin Delano Roosevelt.

More than 30,000 people were detained under the Alien Enemies Act during World War II in a program overseen by the Department of Justice, according to the National Archives. “It was very broad,” Ngai said. “They were newspaper editors, martial arts instructors, Buddhist priests … community leaders who were singled out as enemy aliens.”

While Japanese internment is more widely known, Ebright said it’s also important to recognize other communities were impacted. The law’s “sordid history,” she argued, clearly shows why it shouldn’t be used in the future.

“There were over 15,000 internees of German and Italian descent, and hundreds of thousands of non-citizens of Italian and German descent who were heavily regulated under the Alien Enemies Act regulations during World War II … And so there are many stakeholders in this history, and there are many reasons to look at this law and say, ‘never again,’” Ebright said. “We should not be using this to target any group.”

Rather than targeting people based on their conduct or the threat they posed to national security, Ebright said, the Alien Enemies Act has allowed presidents to discriminate against people based on their identities.

Would an immigrant have any way to challenge their detention or deportation under the law?

Yes, but it’s complicated, according to experts.

The Alien Enemies Act does allow individuals to bring lawsuits challenging their detention, Reisz said. But unlike typical Immigration and Customs Enforcement arrests, which trigger lengthy immigration court proceedings, there would be no automatic judicial review process.

“The only procedural protection is, you have time to settle your affairs before you’re deported,” Ebright said.

Historically courts have deferred to the president during past challenges, Ebright said. She hopes this time will be different.

“My hope is … the courts will realize it is so manifestly a bad faith mistake of a move to say that migration is an invasion, or that non-state actors are foreign governments,” she told CNN.

Could there be other options for Trump to invoke the law?

Fishman, the senior legal fellow at the Center for Immigration Studies, has argued the law could be invoked by Trump or President Biden against Iranians in the US in response to an alleged thwarted Iranian plot to kill Trump. He’s also recommended invoking it in the future to expel Chinese students from the US if the country becomes embroiled in a war with China.

Is it possible to repeal the law?

Some Democratic lawmakers have tried to repeal the Alien Enemies Act in recent years.

“The Alien Enemies Act of 1798 is a xenophobic law that has been used to unjustly target immigrants in the US and should have been repealed long ago,” Sen. Mazie Hirono, D-Hawaii, said last year.

So far, repeal efforts haven’t made it out of committee.

Article written by Catherine E. Shoichet, CNN