All 2020 presidential candidates now support marijuana legalization efforts — even the Republicans

When it comes to marijuana, the Elizabeth Warren of 2012 would probably not recognize the Elizabeth Warren of 2019.

Seven years ago, Warren opposed legalization. In 2015, the senator from Massachusetts said she was “open” to it. In 2016, she said, she voted for it privately at the ballot box. Now she’s one of marijuana’s top cheerleaders on Capitol Hill, championing a measure to protect the pot industry in states where it’s legal.

Warren’s evolution is not unique — in fact, 2020 will see the first presidential race in which every candidate, at least so far, favors some path to legalization.

All 12 official Democratic candidates, as well as the potential Republican hopeful and former Massachusetts governor William F. Weld, told the Globe they now support full nationwide legalization, Canada-style.

President Trump, meanwhile, has said he supports states’ rights to legalize.

“There’s been a tremendous evolution — marijuana legalization, if you look back, was really something for fringe candidates,” said John Lapp, a Democratic national campaign strategist.“It’s just not very controversial at all now.”

For Democrats, especially, being for cannabis legalization might be as much of a litmus test in 2020 among voters as supporting abortion rights. But they must face their past stances with honesty, political strategists say. In 2008, now-Senator Kamala Harris touted her high conviction rates for drug dealers as a district attorney, and Joe Biden, the former vice president — who is likely to run, but hasn’t announced — was long an evangelist for the war on drugs.

A quarter-century ago, then-presidential candidate Bill Clinton did damage control by saying he tried pot while he was a Rhodes scholar in England, but “didn’t inhale.” Running in 2007, Barack Obama found it politically acceptable to admit he had smoked marijuana as a young man, and “the point was to inhale” — but he called it “a mistake.”

Contrast that with this month, when Harris said she, too, inhaled: “Half my family’s from Jamaica. Are you kidding me?”

The political sea change has followed public opinion: About 62 percent of Americans want marijuana to be legal, almost double the 35 percent who said so in 2008, according to the Pew Research Center.

In addition, political analysts say, the changes in candidates’ views were driven by potential tax revenues and job creation, the popularity of reducing mass incarceration, and an aging population interested in the potential medical benefits.

Ten states — including Massachusetts, Maine, and Vermont — and the District of Columbia have legalized marijuana. That means one in four US residents lives in a place where the substance is legal, according to a Globe analysis of census data.

Those states have birthed a booming industry that has organized to lobby lawmakers. One new group, the National Cannabis Roundtable, is led by a former Republican House speaker, John Boehner, who last month called American legalization “inevitable.”

Now politicians, particularly Republicans, have a more politically safe way of supporting marijuana: by advocating for states’ rights, said Steve Fox, a cannabis lobbyist with VS Strategies.

“At this point, the greatest driving factor at the federal level is simply the fact that it’s legal in so many states,” Fox said.

To combat the rising momentum, the antilegalization group Smart Approaches to Marijuana is producing a guide for candidates that it says will be backed by medical associations.

“Candidates will have a simple choice: They can either follow the pot lobby or they can follow the science,” said executive director Kevin Sabet.

On the Republican side, Weld has long been for marijuana. But Trump himself could preempt all competitors by using an executive action or signing a bill into law, like the one sponsored by Warren that would ease the industry’s concerns about federal targeting of state-licensed businesses.

If Trump did either, it would be in line with his thinking as a candidate in 2016, when he said that states should be allowed to experiment with legalization. But his administration’s momentum seemed to die when Trump picked Jeff Sessions to be attorney general. Sessions, who rescinded an Obama-era directive not to prosecute state-legal cannabis businesses, once quipped about the Ku Klux Klan, “I thought those guys were OK until I learned they smoked pot.”

But now with a new attorney general — William Barr testified he would not “go after” legal pot businesses — and Democrats in control of the House, Washington politics may have changed just enough that there could be action soon. Along with passing a large infrastructure bill, loosening marijuana restrictions might be one of the few subjects on which there is bipartisan agreement.

Senator Cory Booker of New Jersey, who has made legalization a core part of his presidential campaign, said his position has much more to do with addressing racial disparities in policing than it does with freedom for recreational use.

“I am pleased to see public sentiment moving as it is, but I have an approach to marijuana legalization that sees it as a justice issue and not just as an adult-use issue,” Booker said. “The damage that the enforcement and prohibition has done to our country is outrageous, unacceptable, and violates our values.”

The potential 2020 candidate who has most publicly evolved on the issue is Democrat John Hickenlooper, who as Colorado’s governor fought against the campaign for his state to become the first to legalize adult recreational use. He has since found his fears of increased underage use to be unfounded, and legalization has dramatically undercut the black market.

“My sense of it now is that states are truly the laboratory of democracy,” Hickenlooper said. “The states should have that ability to go ahead and legalize it, and the federal government should be their partner in this and not their adversary.”

While campaigning in New Hampshire, Warren said she believes marijuana should be fully legal nationally, but her bill with Colorado Senator Cory Gardner, a Republican, reflected the political reality in Washington.

“I do believe in full legalization,” Warren said. “But I will also work with Republicans to allow it to be legalized state by state, if that is the best way.”

Possibly the only potential presidential candidate who disagrees on the issue is Michael Bloomberg, the former New York City mayor. In 2013, he called medical marijuana “one of the great hoaxes of all times.” In 2015, he said that the successful measure in Colorado was “one of the stupider things that’s happening in the country.” Speaking in Canada in January, Bloomberg said the country’s new national cannabis law “is just nonsensical.”

In New Hampshire this election cycle, candidates are likely to be asked about marijuana, as the Legislature there moves toward possibly passing legalization this year. Governor Chris Sununu, a Republican, has vowed to veto such a measure.

But don’t expect many candidates to focus their campaigns on marijuana. It’s not just safe now — it’s too safe.

To stand out in a crowded field, Lapp recommends that a candidate take on affordable health care, immigration, or college debt — “something where there’s some upside and downside, some passion and some risk. I’m just not sure that’s the case with marijuana anymore.”