In April, the US Drug Enforcement Administration (DEA) said that it would review marijuana’s classification as a Schedule I drug, considered the “most dangerous class” of substances.

While the DEA’s announcement is a positive sign, many drug-policy experts think that it’s unlikely the agency will actually decide to change marijuana’s classification, despite a dramatic shift in public sentiment about the drug.

Marijuana’s position in the top tier of the scheduling system — which organizes drugs by their “acceptable medical use and … abuse or dependency potential” — has endured since the 1970s.

“DEA will carry out its assessment of the FDA recommendation in accordance with the [Controlled Substances Act] … and hopes to release its determination in the first half of 2016," the DEA said in a letter to a group of Democratic senators, first obtained by The Huffington Post.

The DEA’s statement was in response to a letter from Elizabeth Warren and other Democratic senators calling for the federal government to facilitate medical-marijuana research, which the Schedule I classification severely hinders.

Rescheduling marijuana into a different classification wouldn’t undo the prohibition on the drug, but it would likely result in increased access to the drug for scientific purposes. Currently, the University of Mississippi is the only institution licensed to cultivate marijuana for research, according to the National Institute on Drug Abuse.

The announcement comes amid a broader reconsideration and embrace of marijuana for medicinal and recreational uses.

‘That clearly is not appropriate’

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The national conversation on marijuana has been shifting for more than 20 years. In late 2015, 58% of Americans said that marijuana use should be legal. As recently as the mid-1990s, only about 25% of Americans held the same position.

And since California began allowing medical marijuana in 1996, 22 other states and Washington, DC, have followed suit, permitting the medical use of the drug in some form.

Organizations like the American Medical Association and American Academy of Pediatrics have recognized marijuana’s therapeutic uses and called on the DEA to reschedule it. Even members of the federal government have joined the push recently.

"I certainly think it ought to be rescheduled,” former US Attorney General Eric Holder said in a February 2016 interview. “You know, we treat marijuana in the same way we treat heroin now, and that clearly is not appropriate.”

That groundswell of support, however, does not appear to be the impetus for the DEA’s review. The agency is acting on an administrative requirement, according to John Hudak, deputy director of the Center for Effective Public Management at the Brookings Institution.

“The advocacy community has suggested that DEA’s statement that they would decide on the Gregoire-Chafee rescheduling petition this summer is a sign that they are moving toward reforming policy with regard to marijuana,” Hudak told Business Insider, referring to a 2011 petition from Govs. Lincoln Chafee of Rhode Island and Christine Gregoire of Washington state.

“The reality is that DEA’s statement offers no such signal,” Hudak said. “The petition has been before the US government for about five years, and DEA has an obligation to rule with the regard to a basic question: Is cannabis properly scheduled?”