Sen. Jeff Sessions (R-Ala.) speaking at the Republican National Convention in Cleveland in July. REUTERS/Mike Segar/File Photo

President-elect Donald Trump plans to nominate Sen. Jeff Sessions (R-Ala.) to be attorney general of the United States, The Washington Post and other news outlets reported Friday. Sessions is a vocal opponent of marijuana legalization whose elevation to attorney general could deal a blow to state-level marijuana legalization efforts across the country.

At a Senate drug hearing in April, Sessions said that “we need grown-ups in charge in Washington to say marijuana is not the kind of thing that ought to be legalized, it ought not to be minimized, that it’s in fact a very real danger.” He voiced concern over statistics showing more drivers were testing positive for THC, the active component in marijuana, in certain states.

Sessions further argued that a lack of leadership from President Obama had been one of the drivers of the trend toward marijuana legalization in recent years. “I think one of [Obama’s] great failures, it’s obvious to me, is his lax treatment in comments on marijuana,” Sessions said at the hearing. “It reverses 20 years almost of hostility to drugs that began really when Nancy Reagan started ‘Just Say No.’ ”

He added that lawmakers and leaders in government needed to foster “knowledge that this drug is dangerous, you cannot play with it, it is not funny, it’s not something to laugh about . . . and to send that message with clarity that good people don’t smoke marijuana.”

Opponents of legalization are cheering the news about the senator from Alabama, saying it may be a potential game-changer in legalization debates around the country. Sessions “is by far the single most outspoken opponent of marijuana legalization in the U.S. Senate,” Kevin Sabet, of the anti-legalization group Smart Approaches to Marijuana, said in an email. “If I were betting on the prospects for marijuana legalization, I’d be shorting.”

Advocates for legalization are, conversely, sounding the alarm. “Jeff Sessions is a drug war dinosaur, which is the last thing the nation needs now,” Ethan Nadelmann, of the Drug Policy Alliance, said in a statement. “Those who counted on Donald Trump’s reassurance that marijuana reforms ‘should be a state issue’ will be sorely disappointed.”

Sessions’s anti-pot positions have been consistent throughout his career. As far back as 1986, he joked that he thought the Ku Klux Klan “was okay until I found out they smoked pot,” according to the New York Times.

At the Senate hearing in April, Sessions spoke approvingly of the “progress” made on drug use, starting with the harsh anti-drug policies of the 1980s. “I can’t tell you how concerning it is for me emotionally and personally to see the possibility that we would reverse the progress that we’ve made and let it slip away from us,” he said. “Lives will be impacted, families will be broken up, children will be damaged.”

He added, “I believe the Department of Justice needs to be clearer” on marijuana legalization.

Whether an Attorney General Sessions would bring such clarity to the office is an open question at this point. President-elect Trump has said that he believes marijuana legalization should be an issue left to the states.

Under Obama, the Justice Department explicitly adopted a hands-off approach to marijuana enforcement in states that have legalized the drug, allowing those laws to proceed without interference provided that a number of enforcement priorities, including keeping pot out of the hands of minors, were met. The announcement of that stance in 2013 played a key role in allowing Colorado and Washington to move forward with their marijuana markets.

“A lot of people forget that [recreational marijuana markets in] Colorado and Washington were pretty much on hold until the governors there received guidance from the Department of Justice,” John Hudak, a senior fellow at the Brookings Institution, said this month.

Even simply reversing that guidance could have a chilling effect in states like Maine and Massachusetts that recently approved legalization. Without a tacit green light from the federal government, governors in those states may be hesitant to move forward with legalization policies that remain at odds with federal laws on the books for more than 40 years.

“I’m still hopeful the new administration will realize that any crackdown against broadly popular laws in a growing number of states would create huge political problems they don’t need and will use lots of political capital they’d be better off spending on issues the new president cares a lot more about,” said Tom Angell of the pro-legalization group Marijuana Majority.

Angell pointed out that recent polls show roughly 60 percent of Americans approve of legalization and that strong majorities of voters across all parties say the federal government should not interfere with state-level marijuana laws.

Asked about the senator’s approach to marijuana issues as attorney general, Sessions’s office responded that it had no information at this moment.

The 2016 election has proved to be the biggest victory for marijuana reform since 2012, with voters in California, Massachusetts, Nevada and Maine approving recreational marijuana initiatives. (Daron Taylor/The Washington Post)