Rob Greene isn't the first plaintiff to sue over the federal government's prohibition on gun possession for users of "unlawful" drugs, which includes medical marijuana in states where it's legal, but to the best of my knowledge he's the only District Attorney to mount a legal challenge to the prohibition. 

Greene, who's served as the Warren County, Pennsylvania District Attorney since 2013, also has a medical marijuana card allowing him to purchase and possess cannabis. As a result, the chief law enforcement officer in the county is ineligible to possess a firearm under federal law, and back in January he sued DOJ over its policy with the help of the Second Amendment Foundation. 

In its latest filing, the Justice Department cited the Supreme Court's decision in Rahimi as a reason to deny an injunction and allow the federal statute to continue to be enforced. 

“The Supreme Court explained that ‘some courts have misunderstood the methodology’ of recent Supreme Court Second Amendment cases as requiring an exact historical match between a modern firearms law and a historical law, but ‘[t]hese precedents were not meant to suggest a law trapped in amber,'” the Department of Justice said in a July 19 filing in federal district court.

Greene’s counsel via the Second Amendment Foundation argued that the Rahimi decision only imposed prohibitions “occurring after a hearing where the defendant is provided due process, and when the court order includes a finding that the individual ‘represents a credible threat to the physical safety of [an] intimate partner.'”

That response notes that Greene’s situation “does not provide for any form of due process, either pre- or post-deprivation, the prohibition is permanent for as long as the individual utilizes a controlled substance, and there exists no nexus between an unlawful user of a controlled substance and the establishment that an individual poses a physical threat to another.”

The DOJ contends that "unlawful" drug users, as a class of people, should be treated as dangerous individuals who would put the safety of the community at risk if they're allowed to exercise their Second Amendment rights. That argument might apply to drug traffickers, but it doesn't make much sense when it comes to medical marijuana patients (or, I would argue, those who use marijuana recreationally). 

It's true that the Supreme Court said in Rahimi that defendants don't need to find an historical twin to a modern gun law in order for it to be upheld, but as the Fifth Circuit Court of Appeals has already pointed out in U.S. v. Daniels, the DOJ hasn't even found a similar prohibition that was in place at the time of the Founding or the ratification of the Fourteenth Amendment. The closest the government could come up with were some state-level bans on possessing a firearm while intoxicated, but nothing that barred individuals who used intoxicating substances from legally possessing a firearm. 

Daniels was one of eight cases the Supreme Court sent back down to lower courts for further review in Rahimi. Ordinarily that would suggest that the Court believes the Fifth Circuit got it wrong, but the cases that were granted cert, vacated, and remanded back to the appellate courts include cases where the challenged statutes were found unconstitutional as well as cases where the status quo was upheld. That's indicative of the Court choosing to simply kick these particular cans down the road to a later date, but it doesn't tell us much of anything about where a majority of the justices stand on the constitutionality of Section 922(g)(3). 

The U.S. District Court judge presiding over Greene's lawsuit has been weighing his request for an injunction since late April, and could issue her decision at any time. We'll have to wait and see if she takes up the DOJ's invitation to rely on non-analogous statutes to keep the law in place, or if the D.A. will soon be able to exercise his right to keep and bear arms without giving up his use of medical marijuana.