Donald Trump scores boost from 24 states in migrant detention battle

Attorneys general from 24 Republican-led states have filed a brief giving Donald Trump significant backing as legal challenges continue over his administration’s use of the Alien Enemies Act to detain and remove certain migrants.

The states argue that courts lack the authority to second-guess a presidential determination that the United States is facing an “invasion” or “predatory incursion” under the law.

Newsweek contacted the DOJ, ACLU and South Carolina AG office for comment via email outside of normal office hours on Tuesday.

Why It Matters

The dispute could redefine the balance of power between the presidency, the courts, and immigration law.

At stake is whether a president can invoke the Alien Enemies Act—a rarely used law from 1798—to detain and remove migrants without meaningful judicial review, based solely on an executive declaration of an “invasion.”

A ruling accepting that view would expand presidential authority in the name of national security, narrow due-process protections for non-citizens inside the United States, and limit courts’ ability to check executive action.

The outcome could shape how future administrations respond to migration and transnational crime, regardless of party, making the case a test of constitutional boundaries rather than a single immigration policy fight.

What To Know

Background of the Legal Fight

The amicus brief—a document filed by someone who is not part of a lawsuit but wants to give the court their opinion or information to help influence how the judge decides the case—was submitted in ongoing litigation before the U.S. Court of Appeals for the Fifth Circuit, where detainees have challenged removals carried out under a 2025 presidential proclamation invoking the 18th-century law.

The states backing Trump contend that the Constitution and long-standing Supreme Court precedent give the executive branch exclusive authority to make national security determinations related to invasion and foreign threats, particularly during times of emergency.

The Alien Enemies Act, enacted in 1798, has historically been used only during declared wars, including World War I and World War II.

Trump’s proclamation marked one of the rare modern invocations of the statute, asserting that the transnational criminal organization Tren de Aragua constituted part of an invasion linked to Venezuela.

Under that reasoning, Venezuelan nationals alleged to be members of the group were designated “alien enemies” subject to detention and removal without the usual immigration court process.

Legal Challenges and Opposition

Opponents of the policy argue that the law does not apply outside a traditional state-to-state conflict and that its use in immigration enforcement violates due process protections.

Several detainees filed habeas petitions in federal court, leading to temporary restraining orders and a series of fast-moving judicial disputes over whether removals could proceed.

The coalition of states, led by South Carolina and joined by Texas, Florida, and others, rejects that argument.

In their filing, the states say judicial review of the president’s determination would intrude on powers textually committed to the executive branch.

They also argue that courts lack clear legal standards to evaluate whether an invasion exists, making the issue a political question beyond judicial review.

Broader Implications

The brief further maintains that the states themselves face direct public-safety and financial consequences from transnational criminal activity and therefore have a strong interest in allowing the federal government to act decisively.

According to the filing, delaying or blocking removals through court intervention undermines both national security and the states’ ability to protect residents from organized crime.

The states’ support comes as federal courts continue to scrutinize the administration’s actions surrounding migrant transfers, including flights that carried detainees to El Salvador in March 2025.

Those events prompted a separate contempt inquiry in Washington, D.C., where a district judge is examining whether federal officials complied with a court order temporarily barring removals.

That inquiry has focused on whether officials acted willfully and whether the order was sufficiently clear to support contempt proceedings.

The Supreme Court has previously signaled skepticism toward lower-court intervention in wartime or national security judgments, but it has not squarely ruled on the statute’s modern application to nontraditional threats.

For Trump, the amicus support from two dozen states represents a notable legal and political boost as courts weigh the boundaries between executive power, immigration law, and judicial oversight.

The outcome could shape how future administrations respond to transnational crime and migration pressures—and clarify whether a law written more than two centuries ago can be adapted to contemporary security challenges.

What People Are Saying

Karoline Leavitt, White House press secretary quoting the Administration’s position on deportations under the Alien Enemies Act, said: “We are confident in the lawfulness of the Administration’s actions and in ultimately prevailing against an onslaught of meritless litigation brought by radical activists who care more about the rights of terrorist aliens than those of the American people.”

U.S. Circuit Judge Patricia Millett on the use of the Alien Enemies Act, said: “Nazis were treated better than Venezuelans deported by Trump.” [Judge Millett was questioning government lawyer Drew Ensign on whether Venezuelans targeted for removal had time to contest the Trump administration’s assertion that they were members of the Tren de Aragua gang, before they were put on planes and deported to El Salvador.]

What Happens Next

The case now moves through the federal courts, with the U.S. Court of Appeals for the Fifth Circuit set to decide whether a president’s invocation of the Alien Enemies Act can be challenged by judges or must be accepted as a nonreviewable national security determination.

At the same time, lower courts will continue handling disputes over specific removals and compliance with past court orders.

If appellate courts reach conflicting conclusions or uphold sweeping executive authority, the issue is likely to advance to the Supreme Court, which would then determine how far presidential power extends under the centuries-old law and how much oversight courts can exercise in modern immigration enforcement.