Slaven Vlasic via Getty Images Former Attorney General Eric Holder believes marijuana should no longer be classified as a Schedule I drug, he said in a recently published interview.

Former Attorney General Eric Holder believes marijuana should no longer be considered a Schedule I substance -- a classification reserved for the most dangerous drugs with no medical use -- he said in a recently published interview with PBS's "Frontline."

"You know, we treat marijuana in the same way that we treat heroin now, and that clearly is not appropriate," he said. "So at a minimum, I think Congress needs to do that. Then I think we need to look at what happens in Colorado and what happens in Washington."

Colorado and Washington have legalized recreational marijuana use over the past few years, and Alaska, Oregon and Washington, D.C., have since followed suit. A number of other states have decriminalized possession of small amounts of marijuana.

"Frontline" conducted the wide-ranging interview on drug policy last year after Holder's departure from the administration, and released it Tuesday along with the program's most recent documentary on the heroin crisis.

Holder has signaled support for rescheduling marijuana in the past, as far back as 2014, when he was still attorney general. During an interview with Katie Couric, he similarly questioned the wisdom of keeping marijuana in the same category as heroin, a drug that is rightly considered to have a high potential for abuse and dependence.

But while the nation's former chief law enforcement officer has expressed disagreement with marijuana's current scheduling, he has been hesitant to propose aggressive action to change it.

At a congressional hearing in 2014, Holder said he'd be "more than glad to work with Congress" to reclassify weed. He echoed those comments in his "Frontline" interview, saying any move to adjust the federal classification of marijuana would have to come from Congress. President Barack Obama has taken a similar stance, while current Attorney General Loretta Lynch has been relatively silent on rescheduling efforts.

But some legal experts say the executive branch -- and more specifically, the attorney general -- actually has the power to reschedule a drug unilaterally. Here's a quick and easy breakdown of how that would work, via the Brookings Institution.

Brookings Institution

Tom Angell, chairman of the advocacy group Marijuana Majority, believes Holder could have done more to address rescheduling as attorney general.

“It’s nice to have Holder’s support for this sensible policy change, but it would have been a lot better if he’d exercised the power to get marijuana rescheduling done while he was still in office," Angell said. "We know that Holder and President Obama are good friends, so I hope the former attorney general encourages his former boss and his successor Loretta Lynch to follow through during these final months of the administration and get the job done."

Moving marijuana into a lower schedule wouldn't make it legal under federal law, but it would, among other changes, open the door for further scientific research that advocates say would lead to a fuller understanding of the drug's medical benefits.

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