An immigrant from Mexico stopped by law enforcement in Maine is at the center of a peculiar case that has the Trump administration arguing for limits on gun rights.

This week, a federal appeals court ruled President Donald Trump’s Department of Justice may continue to prosecute the man on a firearm possession charge.

The DOJ’s case against Alberto Rebollar Osorio, a Mexican citizen who had been living in the U.S. without authorization for about 11 years when an Oxford County sheriff’s deputy pulled him over for speeding on Route 16 in Adamstown Township in 2024, began during former President Joe Biden’s administration. But Trump’s team took up the mantle when he returned to office in 2025.

After being stopped in February 2024, Rebollar Osorio presented the deputy with his Mexican passport and said he was not in the country legally. A Border Patrol agent stationed in the Rangeley area then arrived on scene, according to an arrest affidavit. Rebollar Osorio said there was a pistol in his backpack in the vehicle, and that he had purchased it in the town of Canaan.

A lower court dismissed the federal government’s 2024 indictment of Rebollar Osorio on a charge of possessing a firearm as a person illegally in the country. That offense stems from the Gun Control Act of 1968 that took effect during a tumultuous period of assassinations, and “knowingly violating” it carries up to 15 years in prison. (Rebollar Osorio had no prior criminal record, according to court filings.)

U.S. District Judge Nancy Torresen in Maine ruled later in 2024 that the federal government’s indictment of Rebollar Osorio, who court records indicate is now around 30 years old, violated the Second Amendment and that migrants are among “the people” the amendment says have the right to lawfully possess firearms.

Rebollar Osorio had entered the U.S. through Texas in 2012 when he was 16 years old after a Mexican drug cartel threatened to kill him if he did not join it, according to court records. He joined his two brothers, learned English and is married to a U.S. citizen whom he had been living with in Maine before his arrest.

Torresen wrote the man presented evidence showing “he has spent considerable time working and caring for his family and others in his community, including helping friends, elderly neighbors and even strangers in need.” Court records from 2024 also indicated Rebollar Osorio had “begun the paperwork” to become a U.S. citizen.

The Justice Department then sought to overturn the ruling from Torresen, whom former President Barack Obama nominated to the bench in 2011.

On Tuesday, the Boston-based 1st U.S. Circuit Court of Appeals struck a blow against Torresen’s ruling.

The panel agreed with the Justice Department that Rebollar Osorio should be prosecuted. The ruling came from U.S. Circuit Chief Judge David Barron, who was joined by U.S. Circuit Judge William Kayatta and U.S. Circuit Judge Jeffrey Howard. Kayatta and Barron were both appointed by former President Barack Obama; Howard was appointed by former President George W. Bush.

Barron’s ruling said the prosecution of the Mexican citizen “fits comfortably” within the country’s firearm regulations that date to colonial and founding-era measures to disarm Native Americans, Catholics and others on the condition of having “allegiance” to the nation.

The judge also pointed to a separate case ruling Tuesday that found the traditional enforcement of firearm regulations “aims to reduce the threat posed by a group … lacking a regulable relationship with the government.”

Rebollar Osorio, through legal counsel who did not comment Tuesday, argued the historical regulations cited by the government were “racist” measures aimed at the “preservation of a ruling class.” After Tuesday’s ruling, his criminal case has now been reassigned to U.S. District Judge Lance Walker, according to court records.

The Justice Department did not respond to a request for comment Wednesday.