So what happened to turn marijuana legalization from stoner fantasy to political reality? To start, 21 states and the District of Columbia have passed medical marijuana laws in the past 15 years, and the country hasn’t suddenly become overwhelmed with dangerous potheads. Public outrage over the mass incarceration of nonviolent drug users—a consequence of the zero-tolerance laws put on the books over the past 40 years—has also played a role. And then there’s another factor, far less well known but arguably at least as important: a cherubic, perpetually half-lidded 31-year-old who works in the shadow of Colorado’s capitol building.

His name is Mason Tvert, and it’s no exaggeration to say that without him marijuana would not be legal in Colorado. By changing the way marijuana advocates talked about pot, he changed voters’ minds—and proved to political operatives across the country that a tweaked message could turn this perennial loser of an issue into a campaign winner. Now, as director of communications for the Marijuana Policy Project—the country’s largest organization devoted solely to making weed legal—he’s taking his message, and his irreverent way of selling it, national.