What to Know About the Alien Enemies Act, a 1798 Law Invoked by Trump

The president invoked the law before deporting 250 members of the Venezuelan gang Tren de Aragua, a move challenged by the ACLU and others in court.

A Department of Homeland Security officer stands guard at 26 Federal plaza in New York City, on March 10, 2025. David Dee Delgado/Getty Images

President Donald Trump has issued a proclamation invoking the Alien Enemies Act, a 1798 law providing for deportations of noncitizens during times of war or invasion.

The proclamation targets members of the Tren de Aragua (TdA) gang, which Trump links to the socialist regime in Venezuela. Trump declared TdA a foreign terrorist organization in February.

The case is in legal limbo after several groups sued the administration.

Meanwhile, the act has already been used as the basis for a deportation flight carrying hundreds of Venezuelan nationals to El Salvador under an agreement announced a day earlier.

History of the Law

The Alien Enemies Act was part of the Alien and Sedition Acts enacted in 1798 by the Federalist legislature during the naval quasi-war between the United States and France.

The law authorizes the president to “apprehend, restrain, secure and remove, as alien enemies” citizens of a hostile nation during declared wars or times of invasion.

The law, which has been used only rarely over 227 years, was first invoked against British nationals by President James Madison during the War of 1812.

In 1917, after Congress declared war on Germany, President Woodrow Wilson issued a proclamation that applied to Germans and later to Austro-Hungarians, Bulgarians, and Ottoman nationals. Thousands were registered, and some were interned.

During World War II, President Franklin Roosevelt used the act as the basis for the mass internment of noncitizen Japanese, German, and Italian nationals. The internment of Japanese American citizens was under a different authority.

Deportation Flights Begin

Trump’s proclamation marks the first attempted use of the law since World War II and is the first that doesn’t rely on a state of declared war.

Rather, Trump’s proclamation is based on the language that permits such authority during “any invasion or predatory incursion ... against the territory of the United States, by any foreign nation or government.”

In the proclamation, Trump said that TdA is perpetrating such an invasion “at the direction, clandestine or otherwise, of [Venezuelan President Nicolás Maduro’s] regime.”

A federal judge blocked implementation of the proclamation at about 7 p.m. EDT on March 15.

On March 16, Secretary of State Marco Rubio announced that 250 TdA members had been deported to El Salvador, which had agreed to take deportees that Venezuela has refused to take back, in exchange for a $6 million payment from the United States.

The White House later confirmed that the flight departed before the court issued the order.

Legal Challenges

The proclamation was immediately challenged by lawyers for five of the Venezuelan nationals with support from the American Civil Liberties Union and Democracy Forward.

The complaint cites the unprecedented nature of Trump’s use of the law, noting that it was previously used only in times of war. It also claims the proclamation could be used to deport Venezuelan nationals more broadly.

In an initial ruling, Judge James Boasberg of the U.S. District Court for the District of Columbia ordered at least a two-week delay on the deportation of the five plaintiffs, and in a later ruling granted class-action certification to all affected by the proclamation.

“I do not believe I can wait any longer and am required to act,” Boasberg said on March 15 ahead of his ruling to block immediate implementation of the order. “A brief delay in their removal does not cause the government any harm.”

Attorney General Pam Bondi and the Department of Justice on March 16 filed an emergency motion in the U.S. District Court of Appeals for the District of Columbia.

“This Court should halt this unprecedented intrusion upon the Executive’s authority to remove dangerous aliens who pose grave threats to the American people,” Bondi wrote.

Lawmakers React

Republicans called Boasberg an activist judge who is preventing the deportation of violent criminals from the country.

“It’s ridiculous that a Democratic president can import violent gang members, but a Republican president can’t deport them,” Rep. Mike Collins (R-Ga.) wrote in a post on social media platform X.

Rep. Brandon Gill (R-Texas) vowed in a post on X to file impeachment articles against Boasberg.

Rep. Andrew Clyde (R-Ga.) reposted Gill’s post and offered his support. However, any impeachment effort is unlikely to go far because the removal of a federal judge requires the consent of two-thirds of the Senate.

Few Democrats have issued statements yet, but some have announced opposition to the use of the Alien Enemies Act.

Rep. Juan Vargas (D-Calif.) and other House Democrats on March 13 reintroduced the Neighbors Not Enemies Act, which would overturn the 1798 legislation. Vargas called the legislation a “draconian, wartime law.”

The same bill had been reintroduced in January in the Senate by Sen. Mazie Hirono (D-Hawaii).

Rep. Joaquin Castro (D-Texas) on March 14 said that any effort to use the Alien Enemies Act for deportations would be an “abuse of power.”

What’s Next?

The fate of the proclamation lies in the courts. Democrats or other critics have no other options, given that Republicans control both houses of Congress.

Trump’s use of the law is novel and depends on a claimed link between TdA and Maduro’s regime.

Boasberg’s temporary ruling could be overturned by Bondi’s appeal, or it could be upheld pending further litigation.