A June Quinnipiac poll found that 69 percent of registered voters ages 18 to 34 say that marijuana should be made legal. Pictured: Democratic presidential candidate Hillary Clinton speaks at a campaign event on Nov. 3, 2015 in Coralville, Iowa. (Scott Olson, Getty Images)

One surefire way for Hillary Clinton to shore up support among young voters

Among adults ages 18 to 34, 28 percent said support for legal marijuana would make them more likely to vote for a candidate

A full-throated endorsement of legal marijuana may be just the thing that Hillary Clinton needs to shore up support among wavering millennials, according to polling data from CBS news. But such a move would risk alienating older voters more skeptical of the merits of legal weed.

The Democratic presidential nominee’s “millennial problem” is well documented. Young voters don’t seem to be that energized by her campaign. In a recent Quinnipiac poll only 31 percent of likely voters ages 18 to 34 said they supported her. Nearly as many young voters (29 percent) said they supported third-party candidate Gary Johnson.

Young voters have always been a key part of the Democratic coalition, with 60 percent of them choosing President Barack Obama over the GOP’s Mitt Romney in 2012. So any loss in support among that demographic — to say nothing of a 50 percent drop in four years, if the Quinnipiac poll is accurate — could spell serious trouble for any Democratic candidate.

But there is one thing that younger voters like a lot, and that’s legal marijuana. A June Quinnipiac poll found that 69 percent of registered voters ages 18 to 34 say that marijuana should be made legal. Polling from the Pew Research Center has shown that support is even higher (77 percent) among millennial Democrats. And even millennial Republicans (63 percent) strongly support legalizing weed.

Numbers like those are leading some observers — such as Tom Angell of the marijuana reform group Marijuana Majority — to argue that Clinton could bolster millennial support by becoming more outspoken on marijuana issues. “All the data seems to indicate that endorsing marijuana legalization before Election Day would be a net gain for Hillary Clinton, one which she badly needs in order to help ensure a victory,” Angell writes at marijuana.com.

Similarly, over at New York Magazine, Eric Levitz writes that “there’s no better cure for millennial apathy than legal marijuana.”

In April, a CBS News survey posed a question that sheds more light on this issue. CBS asked American adults whether a candidate’s support for legal marijuana would make them more or less likely to vote for that candidate. Most respondents — 58 percent — said that a candidate’s support for legal marijuana “wouldn’t matter” at all. Eighteen percent said they’d be more likely to vote for a pro-weed candidate, while 21 percent said they’d be less likely.

But there were some interesting differences by respondents’ age. Among adults ages 18 to 34, 28 percent said support for legal marijuana would make them more likely to vote for a candidate. Only 7 percent of this age group said they’d be less likely to vote for a candidate who endorsed legal weed.

These numbers suggest that legal marijuana could give Clinton a boost among younger voters in November. Similarly, Americans ages 35 to 44 are more likely to support (22 percent) than oppose (14 percent) a candidate because she or he supports marijuana legalization.

But among older voters, those numbers are reversed. Nearly one-quarter (24 percent) of Americans ages 55 to 64 say marijuana support would make them less likely to vote for a candidate. And among seniors, a whopping 40 percent say support for legal weed would be a negative, compared with only 6 percent who say it would make them more likely to vote for someone.

It’s difficult to guess what all these numbers would actually mean at the ballot box. Just saying that you’d be “more likely” to vote for someone on account of a particular issue doesn’t mean that you’d go so far as to change your vote solely because of that issue. And it’s impossible to know how any increased support among younger voters might be offset by a drop in support among older voters if Clinton were to endorse legal pot.

It’s also important to keep in mind that marijuana law is not a binary issue. There’s a lot of policy ground to stake out between “full prohibition” and “Colorado-style legalization,” as outlined in this 2015 RAND Corp. report. Clinton could go full-wonk on the marijuana question by, say, voicing support for Washington, D.C.-style non-commercial marijuana legalization (where growing, using and giving away marijuana is legal, but selling it is not).

A middle-of-the-road approach like this would likely garner praise from public health experts, who tend to worry more about the negative impacts of commercial marijuana legalization than about marijuana use overall.

But Clinton has preferred to play it cautious on marijuana policy so far, primarily embracing a “wait-and-see” approach and voicing support for letting states set their own marijuana policies. She has also said that as president, she’d move marijuana out of the most restrictive regulatory category in the Controlled Substances Act.