WASHINGTON — The Supreme Court on Monday hears its latest gun rights case concerning a federal law that bars frequent users of illegal drugs from possessing firearms.

Gun rights advocates argue the law falls afoul of the Constitution’s Second Amendment, which protects the right to bear arms.

The case puts a spotlight on the Trump administration’s mixed messaging on gun rights. Although the Justice Department is defending the law in court, to the annoyance of Second Amendment advocates, it has in other areas backed challenges to firearms restrictions.

The Justice Department turned to the Supreme Court after an appeals court ruled last year in favor of Texas-based Ali Danial Hemani, an alleged regular user of marijuana who had a handgun at his home in the Dallas area when it was searched by the FBI in 2022.

Hunter Biden, the son of former President Joe Biden, was convicted under the same law in June 2024 before being pardoned by his father.

Monday’s is the second gun case currently being considered by the Supreme Court. In January, the justices heard arguments over a Hawaii law that prevents people from carrying firearms onto certain private properties without permission.

The Supreme Court has a 6-3 conservative majority that often backs gun rights, most notably in a 2022 ruling that for the first time recognized a right to bear arms outside the home. That decision spurred a new wave of challenges to existing gun laws, although the Supreme Court appeared to take a step back two years later when it upheld a federal law that prohibits people subject to domestic violence restraining orders from possessing firearms.

Lower courts are divided over whether the restriction on gun ownership for frequent drug users infringes on the Second Amendment.

Hemani successfully challenged his indictment in district court and the New Orleans-based 5th U.S. Circuit Court.

The law could not be constitutionally enforced merely because the government alleged someone is a regular drug user, the appeals court found, basing its ruling on an earlier precedent.

The government instead must show that the gun owner was under the influence of the drug at the time of the arrest, the appeals court ruled.

Prosecutors did not do so in Hemani’s case.

Hemani, a dual citizen of the United States and Pakistan, was already under FBI scrutiny when he was arrested, Solicitor General D. John Sauer said in court papers. The government has asserted that Hemani and his family have ties with Iranian entities hostile to the United States, although he has faced no specific charges relating to those links.

A handgun, marijuana and cocaine were found when the FBI searched his home in 2022.

In defending the law, Sauer said it was consistent with the history and tradition of the Second Amendment, as explained by the Supreme Court in its 2022 ruling, for “dangerous persons” to be temporarily disarmed.

“History and precedent establish that legislatures may temporarily restrict the possession of firearms by those who threaten the safety of the community,” Sauer wrote, adding that a habitual drug user fits the definition of a dangerous person.

Hemani’s lawyers counter in their own filings that the law is too vague, as it doesn’t define what an “unlawful user” of drugs would be. Millions of Americans regularly consume marijuana, which is legally available in many states, they point out. Marijuana remains illegal under federal law.

Even regular consumption of a drug does not make someone a habitual user or addict, Hemani’s lawyers say, adding that “there is no historical tradition in this nation of stripping anyone who consumes an intoxicant a few times a week of the right to keep a firearm in the home for self-defense.”