Cannabis legalization, an issue that 68 percent of Millennials support, will likely be on the ballot in at least seven key states. That means Republicans may have an opponent they didn't expect (other than Trump).

To win a presidential election, Republicans count on the fact that Democrat-leaning young people historically do not vote. But in 2008, more young people cast a ballot than ever before to help elect President Barack Obama. The Millennial generation is now the largest in the U.S. and has the power to determine the 2016 election, according to a study by The Center for Information and Research on Civic Learning and Engagement at Tufts University.

Leslie Bocskor, founder of marijuana business consulting firm Electrum Partners, says he believes cannabis ballot initiatives in Arizona, California, Florida, Maine, Massachusetts, Nevada, and Ohio will draw youth voters -- ultimately impacting the presidential election.

"We will see cannabis ballot initiatives decide the presidency by delivering key battleground states," Bocskor says. 

According to the most recent Gallup poll on the issue, 58 percent of Americans support legal marijuana, marking the third consecutive year the majority of respondents support ending pot prohibition. Bocskor says the combination of an election year and marijuana on the ballot will bring people to the polls who are not usually politically active.  

"Who are they going to vote for? Bernie or Hillary, versus Trump or one of the Republicans?" Bocskor asks rhetorically. "If you get that many people out to the polls, it's going to bend the turnout curve and skew dramatically to a Democratic candidate." 

Bocskor's analysis makes perfect sense on a cocktail napkin, but a closer look at historical precedent shows that it is difficult to get young voters to rock the polls. After a record number of young voters came out in 2008, not nearly as many came out for 2012. Another issue: Marijuana is no longer an ace up the Democratic party's sleeve. While pot used to belong to Democrats and liberals, marijuana legalization has found a safe haven and logistical home in state's rights, bending the legalization effort to Republican and Libertarian sensibilities. 

Studies looking at 2012 voter turnout in Colorado, Oregon, and Washington have found that ballot measures legalizing marijuana did not drive younger voters to the polls. According to the Current Population Survey, the number of young voters actually decreased by 1.2 percent across all three states from 2008 to 2012. 

Another study by professors from Kent State University and the University of Denver found that Democrats did not benefit from marijuana being on the ballot four years ago. But the study found that cannabis ballot measures did increase the overall voter turnout in Colorado and Washington in 2012 (though not in Oregon, where the initiative did not pass). The bottom line is that marijuana ballot initiatives can drive more people to the polls, but they don't seem to help either party or affect the number of young voters. 

Pot is for Republicans

Tom Angell, the chair of pro-legalization group Marijuana Majority, says marijuana is a mainstream, bi-partisan issue but will not swing the election.

"You put marijuana on the ballot, it's going to boost turnout from young people and that's going to help Democrats. That's the conventional wisdom that has been parroted and I don't really buy that," he says. "I think marijuana initiatives only help candidates that support the marijuana initiative that the voters are turning out to support."

Angell says marijuana legalization does not automatically help the Democrats. He says ballot measures only attract voters who support that ballot initiative, regardless of age or political party. Rallying new voters or motivating people who don't usually vote is an uphill battle. Also, he adds, marijuana is not the partisan issue that some might suspect. 

Marijuana Majority's own survey, conducted in August 2015 by Public Policy Polling, found that Republicans and Democrats support state-legalized marijuana. (A caveat about the data: Some have criticized PPP's methodology and perceived liberal bias.) The survey found that 64 percent of Republican voters in Iowa, 67 percent in New Hampshire, and 66 percent in South Carolina support states that want to carry out their own marijuana laws without fear of federal law. As for Democrats, 80 percent in Iowa, 77 percent in New Hampshire, and 59 percent in South Carolina support state legalized pot without federal interference.

Pot for President

When it comes to the candidates running for president, Bernie Sanders supports a federal law that would legalize marijuana, and tax and regulate it like alcohol. Clinton supports states' rights to adopt their own laws and for more research to be done for medical benefits. As for the Republicans, Cruz opposes legalization but supports states' rights, Rubio is totally opposed, and Trump says marijuana is "bad" in general but supports states' rights and medical marijuana. 

While the legalization of marijuana is a sexy topic, there are people who are earnestly fighting against it. Kevin Sabet, who cofounded nonprofit Smart Approaches to Marijuana with Patrick Kennedy, promotes decriminalization and drug law reform, but not all-out legalization. Sabet is often refered to as the legalization effort's opposition. 

Sabet doesn't think marijuana ballots will sway the election and he doesn't think that many voters are motivated by legalization. He thinks jobs, taxes, and fighting terrorism are bigger issues than ending pot prohibition.

"I don't think marijuana is a mainstream issue," Sabet says. "I think states' rights is a mainstream issue and legalization advocates have found a clever way to fit their policy into states' rights."

The Popular Choice

Allen St. Pierre, the executive director of marijuana lobbying group NORML, takes a different point a view. He says a greater percentage of people vote for marijuana initiatives than they do for presidents.

Consider the 2014 mid-term elections in Florida, he says. A medical marijuana ballot there narrowly lost, scoring only 58 percent of the vote (not the 60 percent majority needed). But look at presidential elections: President Obama won 51 percent of the vote in 2012. Bush also won 51 percent and Bill Clinton got 49 percent. There's a good chance that no president will ever rack up 60 percent of the vote, St. Pierre says. 

"The political machinery knows that marijuana is a popular populist issue in the United States," he says.

St. Pierre says pot might not determine the election, but marijuana has come a long way from its murderous rep in Reefer Madness and its fight-the-man role in the 1960s, to its current status as the sexiest industry in the U.S.

When it comes to what's more appealing--the presidential candidates or cannabis--there is perhaps no contest. 

"It can be said that marijuana is more popular than politicians themselves," St. Pierre says. "A politician against marijuana will not be a politician for much longer."