As people across the country observed yesterday's unofficial holiday celebrating marijuana, aka “420,” it was the first time they were doing so under the Trump administration.

President Trump himself hasn’t spoken extensively about weed or the legalization debate, though suggesting he favored medical marijuana use when asked about it once on the campaign trail.

“I think that as far as drug legalization, we talk about marijuana, and in terms of medical, I think I am basically for that. I’ve heard some wonderful things in terms of medical,” he said at an MSNBC town hall event in Wisconsin in March 2016.

Sam Kamin, a law professor specializing in marijuana law policy at the University of Denver, said the administration has “largely used rhetoric” in its approach to marijuana policy so far.

Matt McClain/The Washington Post via Getty Images Senator Jeff Sessions (R-AL) is seen before his Attorney General confirmation hearing at the Russell Senate Office Building, Jan. 10, 2017, in Washington, DC.

While the administration hasn’t changed any law or law enforcement policies thus far, the signals are “enough to give the industry pause,” he noted.

“No one knows exactly what, if anything, they will do next,” Kamin told ABC News. “They might begin enforcing federal law against marijuana businesses or they might alter the current enforcement memos to indicate where their priorities lie. They can’t force the states to recriminalize marijuana or to enforce the federal prohibition.

“But they can make things very unpleasant even for those who are attempting to comply with state laws regulating their conduct,” he said.

Twenty-one states and the District of Columbia have decriminalized small amounts of marijuana, according to the National Conference of State Legislators. But pot use remains federally illegal, so the Trump administration could crack down at any time because state can’t override federal law.

While Trump appears to be open to hearing arguments from various sides of the discussion when it comes to legalization, U.S. Attorney General Jeff Sessions has been a longstanding critic of the drug.

At a Senate hearing last April, Sessions said “good people don’t smoke marijuana” and it is “not the kind of thing that ought to be legalized.”

Such comments and other remarks Sessions has made on the issue prompted marijuana legalization advocates to protest his confirmation hearing, and later hand out free joints in parts of Washington, D.C., on the morning of the inauguration in protest.

Sessions talked more recently about his views at the National Association of Attorneys General winter meeting in February, when he said that he’s “dubious” about marijuana.

“I’m not sure we’re going to be a better, healthier nation if we have marijuana sold at every corner grocery store,” he said, though noting that “states can pass whatever laws they choose.”

One counter-voice that’s coming from within Trump’s inner circle but outside the administration is that of Roger Stone, the longtime Republican political consultant and friend of Trump’s.

He is pushing against Sessions’ perceived stance on Twitter this morning, posting a tweet that reads, “The people have spoken @realDonaldTrump. Don’t let Jeff Sessions’ draconian views on 420 run roughshod over states,” with a link to an article that includes CBS News poll results that find 61 percent of Americans want marijuana to be legalized.

Stone, who is open about both his marijuana use and admiration for his former boss President Richard Nixon, this morning shared a photo on Twitter of a bong in the shape of Nixon with the caption “Happy 420! #NixonBong.”

Kamin said the “billion-dollar question” is how much Trump will listen and might be affected by the views of Sessions and others.

“It’s pretty clear that going after the regulated marijuana industry is not high on Trump’s to-do list,” Kamin added. “But it does seem to be a real concern of Mr. Sessions’. How much free rein the AG gets is a question that only a very small handful of people know.”