Last month, as he was losing renomination for a second term, D.C. Mayor Vincent Gray signed the city's latest decriminalization bill. It was set to go into effect this year, and reduce possession of small amounts of pot to a parking-ticket offense. For a while, it was unclear whether Congress would fight this, and I remember debating with a younger Republican member about why the law would come under any scrutiny. He reminded me just how old some of the Republican conference is, and how many view legal or decriminalized drugs as something of the left and of the hippies.

He predicted today's hearing, which was inconclusive. Rep. John Mica, who's 71, chaired the subcommittee's probe of the bill, taking testimony from local law enforcement and giving Republican peers time to debunk the idea that marijuana is harmless—which isn't even part of the reason for decriminalization.

Over 10 minutes, (Louisiana Rep. John Fleming) challenged the city for rejecting the science that showed marijuana "modifying" brains (as basically any activity does) and warned that in Colorado, the legalization of weed had led to "fourth-graders" selling drugs. Plus, legalization was expensive, and libertarians ignored the costs.

“No one is here to negate the District law; we are looking at the implications and the enforcement regime with 26 different agencies responsible for enforcing different penalties,” said Rep. John L. Mica, R-Fla., who held the gavel during the subcommittee hearing, plus a faux joint that was rolled by a member of his staff.

After holding multiple hearings on the administration’s approach to enforcing the federal prohibition on pot in the states that have legalized the drug, Mica emphasized he was not “singling out” D.C., but wanted to look at the potential conflicts that decriminalization could create. On Friday, the chairman of the Oversight and Government Reform Subcommittee on Government Operations heard testimony from law enforcement officials representing the Metropolitan Police Department, the Department of Justice and the Park Police on those issues.

At the hearing’s conclusion, Mica said he was still unsure if Congress would intervene to stop the bill during the 60-day review period that lasts through mid-July.

“We will continue this series …” he said, later telling reporters that he wants to know, “Has the narcotic changed in its potency? Does it pose an even greater risk?” Mica intends to look at all of that, and says his views on decriminalization are still evolving. “I’m learning as we go through these hearings.”