In a controversial move, the Trump administration has revived a long-dormant 85-year-old immigration law, using it to criminally charge undocumented immigrants for failing to register with the federal government — a requirement that most immigration attorneys say hasn’t been enforced in over seven decades.
The Alien Registration Act of 1940, originally passed during World War II amid widespread fears about foreign allegiance, is now being deployed as part of a broader push by federal authorities to encourage “mass self-deportation” and fulfill one of the administration’s longstanding policy goals: what it calls the largest deportation effort in U.S. history.
Federal law enforcement officials have already begun charging individuals under the law’s registration provision in Louisiana, Arizona, Montana, Alabama, Texas, and Washington, D.C. The statute requires all non-citizens who remain in the United States for more than 30 days to register with the government and submit fingerprints. Failure to do so is now being prosecuted as a federal misdemeanor, carrying penalties of up to six months in prison or a $1,000 fine.
A Legal Catch-22 for the Undocumented
Immigration law experts warn that the administration’s revived registration effort places undocumented immigrants in a constitutional and legal double bind. Those who comply with the registration requirement must divulge incriminating information — including details of unlawful entry — potentially subjecting them to detention or removal. But choosing not to register could now expose them to criminal prosecution.
“The sort of obvious reason to bring back registration in the first place is the hope that people will register, and therefore give themselves up effectively to the government,” said Jonathan Weinberg, a law professor at Wayne State University.
According to the Department of Homeland Security (DHS), the goal is to create a “safer path” for undocumented immigrants and enforcement agencies by encouraging individuals to voluntarily leave the country — a process the department bluntly calls “mass self-deportation.“
In February, DHS announced new enforcement guidelines and released a seven-page registration form that undocumented immigrants must complete under penalty of perjury. The form collects biographical information, contact details, and immigration history. DHS estimates that up to 3.2 million non-citizens currently residing in the U.S. are unregistered and subject to the requirement.
Legal Backlash and Early Court Rulings
In response, the Coalition for Humane Immigrant Rights (CHIRLA) and other advocacy organizations filed a federal lawsuit in March challenging the administration’s revival of the 1940 law, arguing it violates due process and subjects immigrants to retroactive punishment.
U.S. District Judge Trevor McFadden, a Trump appointee, expressed skepticism of the administration’s enforcement switch during preliminary hearings, calling it a “big switcheroo.” However, in April, McFadden denied a request for a preliminary injunction, ruling that the plaintiffs had likely not demonstrated sufficient legal standing to sue. The case is now on appeal.
Meanwhile, federal prosecutors have filed charges against multiple individuals for non-registration — many of whom were already in deportation proceedings. For most public defenders, it marks the first time they’ve seen charges brought under this section of the Alien Registration Act.
Dormant Law, Modern Enforcement
Although one provision of the 1940 law — criminalizing advocacy to overthrow the U.S. government — was used during the Cold War to target alleged fascist and Communist sympathizers, the registration requirement has largely gone unenforced since the 1950s.
Some immigrants are already considered “registered” under current law — such as those with pending lawful permanent residency applications or those granted humanitarian parole. However, millions of undocumented residents are not, and the administration’s recent directives aim to close that gap.
To date, DHS reports that 47,000 undocumented immigrants have registered using the new form since enforcement began in April.
As the legal fight continues, immigration advocates say the revived use of the Alien Registration Act may signal the administration’s broader intent to create civil and criminal traps for immigrants — compelling them to either self-incriminate, face prosecution, or leave.
