Joe Rogan, Snoop Dogg, and Virgin Group founder Richard Branson will appear in the crowd-funded documentary called the The Culture High, opening October 17 in limited theaters. In it, they explain their opposition to the war on drugs and their support for marijuana legalization. Branson shared this trailer for the movie in a post on Virgin's website on Wednesday:

One of the big questions raised by the trailer is why politicians are taking so long to embrace legalization and medical marijuana when both issues have so much support. (About 58 percent of Americans back full legalization, according to Gallup.)

When I posed the question to experts on social movements, they said marijuana just doesn't have the priority among the electorate or kind of fundraising potential that politicians need to take on an issue.

Politicians generally need a concerted movement "that will give [them] time and money and networks [they] can't get otherwise," said Daniel Schlozman, a political scientist at Johns Hopkins University, in a previous interview. "Without that kind of preference intensity, if you're [Senator] Bernie Sanders, you're going to want to talk about social democracy, and if you're [Senator] Elizabeth Warren, you're going to want to talk about the banks. There's no particular reason for you to dilute your core efforts to move the party."

But as the political pressure builds, some politicians are beginning to move toward public opinion on the issue. Likely 2016 presidential candidate Hillary Clinton previously said she supports medical marijuana "for people who are in extreme medical conditions" and is open to letting the states act as "the laboratories of democracy" for full legalization efforts.

If Clinton's comments are any indication, prominent Democrats are at least preparing for marijuana to turn into a national political issue in the future.

To learn more, check out Vox's war on drugs explainer, marijuana legalization explainer, and 24 maps and charts that explain marijuana.

