The Alien Enemies Act of 1798 and Its Revival in 2025

On Saturday, March 15, 2025, a federal judge in Washington named James Boasberg held an emergency hearing on a weekend. That morning, the White House had made public a proclamation invoking a law passed when John Adams was president, declaring that a Venezuelan gang was carrying out an invasion of the United States. Lawyers for several Venezuelan men in immigration detention asked the court to stop their removal. The judge issued a temporary order blocking deportations under the proclamation and, from the bench, said that any planes already in the air should be turned around. They were not. By the next day, planes carrying well over a hundred Venezuelan men had landed in El Salvador, where the men were taken to a maximum-security prison built for gang members. Many of them, according to later reporting, had never been charged with a crime in the United States. None had been given a hearing on whether they belonged to the gang at all.

In short: The Alien Enemies Act lets the president detain and remove citizens of a hostile nation during a declared war or an invasion by a foreign government. Its use in 2025 against alleged gang members during peacetime raised two questions the courts have had to answer: whether the law applies at all, and what process people must receive before they are sent away.

A law from the quasi-war with France

In the summer of 1798, the United States was fighting an undeclared naval conflict with revolutionary France, and the Federalist majority in Congress passed four laws now known together as the Alien and Sedition Acts. Three of them have long since expired or been repealed. The Sedition Act, which made it a crime to publish false and malicious writing against the government, became one of the most reviled laws in American history. It lapsed in 1801, and Thomas Jefferson pardoned those convicted under it.

The Alien Enemies Act, signed on July 6, 1798, is the one that survived. Today it is codified in Title 50 of the U.S. Code. Its core provision is short. Whenever there is a declared war between the United States and a foreign nation or government, or whenever an invasion or predatory incursion is perpetrated, attempted or threatened against U.S. territory by a foreign nation or government, and the president makes a public proclamation of that event, then natives, citizens, denizens or subjects of the hostile nation who are 14 or older and not naturalized can be apprehended, restrained, secured and removed as alien enemies.

Notice what the trigger requires: war, or an invasion or incursion by a "foreign nation or government." The law was written to deal with subjects of an enemy state during wartime, people who might owe allegiance to the government the country was fighting.

Three wars, and the camps that followed

The law has been invoked only three times before 2025, each during a declared war: the War of 1812, the First World War and the Second World War.

During the Second World War, proclamations issued in December 1941 authorized the arrest of Japanese, German and Italian nationals deemed dangerous. Thousands were detained in Justice Department internment camps, and some were held well after the war ended. This was separate from the mass incarceration of Japanese Americans under Executive Order 9066, which relied on different authority and swept in citizens, but the two programs ran side by side and shared some of the same assumptions about loyalty.

The Supreme Court considered the law in Ludecke v. Watkins in 1948, the case of a German national ordered deported after the fighting had stopped. The Court held that the war had not formally ended, since no peace treaty had been concluded, and that whether a person was an alien enemy subject to removal was largely for the executive to determine. The majority read the courts' role as narrow, limited mostly to questions such as whether the person is in fact an enemy alien of the age covered. Four justices dissented.

That precedent cast a long shadow over the 2025 litigation. It also left open the questions the 2025 proclamation forced into the open.

The 2025 proclamation

The March 2025 proclamation declared that Tren de Aragua, a criminal organization that began in a Venezuelan prison, was perpetrating an invasion or predatory incursion against the United States, and that it was acting at the direction of, or in concert with, the Venezuelan government of Nicolás Maduro. On that basis, it said Venezuelan citizens 14 and older who were members of the group and not naturalized or lawful permanent residents were subject to detention and removal as alien enemies.

That proclamation stretched the statute in several ways at once. There was no declared war with Venezuela. A criminal gang is not a nation or government, which is why the proclamation asserted a link to the Maduro government. And the definition of the covered group depended entirely on an allegation of membership, a factual question that the people being removed had no chance to contest before boarding.

Reports later indicated that many of the men had been identified in part through tattoos or associations that their families and lawyers said had nothing to do with the gang. Some had no criminal record anywhere. The government argued that the absence of a criminal record did not prove the absence of membership.

The Court steps in, twice

The legal fight moved fast.

On April 7, 2025, in Trump v. J.G.G., the Supreme Court vacated the order Judge Boasberg had issued, by a vote of 5 to 4. The majority said the challengers had filed in the wrong form and the wrong place: claims like theirs had to be brought as petitions for habeas corpus in the federal district where they were held. But the Court also said, and all nine justices agreed on this point, that people subject to removal under the Act are entitled to notice and an opportunity to seek habeas relief. The notice had to come within a reasonable time and in a manner that would allow them to actually seek that relief before removal.

Days later, lawyers learned that detainees in north Texas were being given notices in English and told they could be removed within a day. Late on the night of April 18 into April 19, the Supreme Court issued an unusual overnight order directing the government not to remove members of the putative class from the United States until further order. In May 2025, in A.A.R.P. v. Trump, the Court explained itself: notice roughly 24 hours before removal, without information on how to challenge it, did not satisfy due process. The Court sent the case back to the lower courts to decide what notice was enough, and to address the underlying question of whether the Act could be invoked this way at all.

Justices Samuel Alito and Clarence Thomas dissented from that ruling, arguing the Court had moved too fast and overstepped its role.

Those orders mattered most to people who had not yet been put on planes. They did little for the men already in El Salvador, whom the U.S. government said were outside its custody and control. In July 2025, the men held in the Salvadoran prison were returned to Venezuela as part of an exchange between the two governments.

Whether the Act could lawfully be used against a gang during peacetime has been litigated in the lower courts since. That question, with its large implications for presidential power, may well come back to the Supreme Court. Our court watch page tracks the Court's opinions and emergency orders as they come.

The strongest case for the government, and its limits

The government's best argument goes like this. The Act's text is broad. It covers not just war but "invasion or predatory incursion," and the president is the official the Constitution charges with protecting the country from foreign threats. Ludecke said courts have little business second-guessing the president's judgment about wartime enemies. Transnational criminal organizations can be violent and well-organized, and some act with the tolerance of hostile governments. If a foreign state uses a gang as an instrument against the United States, why shouldn't the law apply?

That argument takes a real problem seriously, and progressives should too. Communities across the country, including immigrant communities, are harmed by gang violence, and Venezuelans fleeing Maduro's government have been among its victims.

The answer is in the words the 1798 Congress chose. "Invasion" and "predatory incursion" describe military-style acts by a nation or government, not criminal activity by a gang, however serious. Ordinary immigration law already provides for the removal of people who commit crimes or belong to criminal organizations, through procedures that let them contest the facts. The Act's use here was valuable to the government precisely because it skipped those procedures. A reading of an eighteenth-century war statute that lets a president declare a peacetime invasion and remove people on an allegation of membership, without a hearing, is not a narrow reading. Even the Supreme Court majority that sided with the government on venue insisted on notice and a chance to be heard.

There is also the broader structural point. Ludecke was decided in a declared war, with a peace treaty still pending. The idea that courts should defer heavily to the executive in wartime has always come paired with the expectation that a war actually exists. Detaching that deference from war would hand the executive a power the Constitution gives to Congress.

Why the 1798 statute still matters

It may seem strange that a law from Adams's presidency could be used against people in the twenty-first century. The reason is mundane: Congress almost never repeals old laws, even ones it would not pass today, because doing so takes time and political capital and rarely seems urgent. The Alien Enemies Act sat quietly for most of the twentieth century after 1945. That is how dormant powers stay available.

Members of Congress have introduced bills to repeal the Act, and those efforts gained new attention after 2025. A Congress that will be under Democratic control from January 2027 could take up that question, though nothing is certain about whether such a bill would pass or be signed. Our democracy and rule of law topic page collects reporting on these emergency and wartime powers.

The founders argued about this too

It would be a mistake to treat the 1798 law as a relic everyone in the founding generation accepted. The Alien and Sedition Acts provoked one of the first great constitutional fights in the country's history.

James Madison and Thomas Jefferson answered them with resolutions adopted by the Virginia and Kentucky legislatures in 1798, written anonymously at the time. Their main targets were the Sedition Act and the companion Alien Friends Act, which let the president deport any noncitizen he considered dangerous, in peacetime, without a hearing. They argued that such powers exceeded what the Constitution gave the federal government and threatened liberty itself. The Alien Friends Act was allowed to expire after two years. Its wartime sibling, aimed at subjects of enemy nations, drew less objection, because it was tied to war, a situation in which most people accepted that the government needed extra powers.

That distinction is the heart of the modern dispute. The power the founders were most suspicious of was a peacetime power to remove people the executive deemed dangerous, on the executive's say-so. The power they tolerated was a wartime power over enemy nationals. Using the surviving wartime statute against people accused of gang membership, with no war declared, comes close to reviving the peacetime power that the founding generation let lapse.

The word "invasion" also appears elsewhere in the Constitution: in the clause allowing habeas corpus to be suspended in cases of rebellion or invasion, and in the promise that the federal government will protect each state against invasion. Courts have generally been reluctant to decide what counts as an invasion under those clauses, treating the question as political. That reluctance cuts in a dangerous direction if it means a president's declaration settles the matter. If the word can be stretched to cover migration or crime, it carries with it not only the Alien Enemies Act but potentially other emergency powers tied to the same term.

What you can do

• Ask your representatives about repeal or reform. Find your House member and senators with our lookup tool, which gives phone numbers, contact forms and their latest votes. Ask whether they would support repealing the Alien Enemies Act or limiting it to declared wars with clear due-process requirements.
• Follow the ruling that comes next. The lower courts' answers on whether a gang can be an "invasion" will likely shape any Supreme Court decision. The court watch page lists opinions and emergency orders with the Court's own summaries.
• Support the lawyers who file habeas petitions. The 2025 cases were won in the hours between a notice and a flight by lawyers who were ready. Our directory of nonprofits lists legal-aid and immigrant-rights groups in every state that do this work.
• Talk about due process, not only about immigration. A government that can remove people on an unproven label without a hearing has acquired a power that does not stay confined to one group. That argument reaches people who disagree with you about the border.

The law of 1798 was written for a world of sailing ships and hostile monarchs. Its revival tested whether the protections Americans have built since then still hold when a president reaches back for an old power. So far, the courts have said that at least some of them do.