Gerry Goldstein was as surprised as anyone to get an invitation to speak at the NRA’s annual convention in Dallas earlier this month.

Or as he put it: What’s an “aging Jewish hippie” doing in a place like this?

To be clear, Goldstein is more than an aging Jewish hippie. He’s long been one of America’s best-known defense lawyers. He’s represented everybody from drug-loving gonzo journalist Hunter S. Thompson to Panamanian dictator Manuel Noriega to Mexican drug lord Juan García Abrego.

In 1979, High Times magazine named Goldstein one of America's top 10 dope lawyers. In 1996, Texas Monthly wrote a profile of him headlined "The High Times of Gerry Goldstein."

The man knows a good bit about illegal substances. But a gun guy? Not really.

"I don't have a gun and I don't see why we need assault weapons," he told The Dallas Morning News in a recent interview.

Gerald Goldstein walks out of the Tom Green County Courthouse in San Angelo April 9, 2008. (NATHAN HUNSINGER)

Nevertheless, there he was at the podium at the NRA convention, exactly because he’s a drug attorney who understands how the nation’s Byzantine drug laws could threaten gun owners.

Legal marijuana use is expanding across America. Recreational marijuana is legal in nine states and medical marijuana is legal in 29 states. That doesn’t include Texas, which permits marijuana use under tightly controlled conditions. The Texas law enacted in 2015 allows patients with intractable epilepsy to treat the disease with cannabis oil low in THC, the psychoactive chemical in marijuana.

But under federal law, legal pot users could still lose their right to carry firearms.

As far as the federal government is concerned, marijuana remains a Schedule 1 drug. The Drug Enforcement Administration defines Schedule 1 drugs as having “no accepted medical use and a high potential for abuse.” Heroin and LSD are listed in the same category as marijuana.

Federal law prohibits any unlawful user of marijuana — or any other federally restricted substance — from purchasing guns.

Federal law trumps state law, according to the U.S. Constitution’s Supremacy Clause.

The NRA doesn't take an official position on marijuana use, but it's not hard to figure that some percentage of the 50 million or more Americans who own guns use marijuana. An equally large number identify as "current" marijuana users.

A marijuana plant grows inside Ultra Health's cultivation greenhouse in Bernalillo, N.M. (Susan Montoya Bryan / The Associated Press)

Attorney Richard Feldman, a longtime NRA member and former lobbyist for the gun organization, sees a natural alliance between gun rights activists and people like Goldstein, a longtime member of the National Organization for the Reform of Marijuana Laws (NORML).

Feldman, a Republican from New Hampshire, favors ending the prohibition on marijuana, which he sees as providing cover to those who would use an unnecessary law to curtail the Second Amendment rights of citizens.

It’s not an exaggerated claim, Sarah Gervase, the NRA’s assistant general counsel, said at a law symposium at the NRA convention this month. Gervase noted the Honolulu Police Department recently sent out letters to legal users of medicinal marijuana informing them that they had to forfeit their weapons. The letters were sent out after Hawaii’s first medical marijuana dispensary opened in August.

The Justice Department’s Bureau of Alcohol, Tobacco, Firearms and Explosives has made clear its intention to enforce the marijuana prohibition spelled out on gun purchase forms. In a letter to all federally licensed gun dealers, the bureau stated: “Any person who uses or is addicted to marijuana, regardless of whether his or her state has passed legislation authorizing marijuana use for medical purposes ... is prohibited by federal law from possessing firearms or ammunition.”

The problem for Goldstein is that the same branch of government that enforces laws — the executive branch — is also defining laws through regulations. The DEA decided in 2016 to keep marijuana a Schedule 1 drug — a higher classification than Schedule 2 drugs, like cocaine, methamphetamine and fentanyl.

There are sub-agencies of agencies that create regulations, Goldstein said. “Do we want our legislators to hand off their law-making duties to the executive branch? It is something we all need to be concerned about,” he said. “Federal regulations have become so complex, nobody can be expected to know them all.”

Though Goldstein is best known for representing those charged with dope crimes, one of his most celebrated wins was a 1978 appeal of a gun case. Goldstein appealed a case involving several Texas men who carried out a daring jailbreak from a Mexican prison across the border from the West Texas town of Eagle Pass. The incident, known in the media as the Piedras Negras jailbreak, resulted in the Texans freeing about a dozen American prisoners charged with drug offenses from the Mexican jail. Nobody was hurt in the raid, but the U.S. government subsequently charged the men with violating gun trafficking laws by bringing a sawed-off shotgun across the border for the raid.

Goldstein won the appeal by arguing that the Texans did not knowingly and intentionally commit a crime because the gunrunning statutes were spelled out in a thicket of administrative regulations that the men could not have been expected to know.

“To find out whether taking a shotgun across the border violated the law, you had to go to the code of federal regulations,” Goldstein said.

The same argument of intent could be used to defend someone who runs afoul of the law when it cuts across gun purchases and marijuana use, Goldstein said, adding: “Why should a gun seller be in peril of breaking the law for selling to someone who lies about being a marijuana user?”

Millions of people are affected by laws that are at cross-purposes and subject to selective enforcement, he said.

“These regulations are so complex,” Goldstein said. “No one can be expected to know them all.”

dtarrant@dallasnews.com

Twitter: @davetarrantnews