Bernie Sanders spent the better part of three decades in national politics trying to bring ideas that would strike most of the democratic world as fairly conventional into the mainstream of American politics.

From 1990 through 2015, the congressman-then-senator from Vermont had to content himself with a cult following on the progressive left and a reputation for decency that eludes most politicians. Largely unavailable to him were the conventional tools factional and party leaders use to advance their causes. Sanders was a relatively infrequent guest on national news programs. He seldom campaigned outside his home state for Democrats, and when he did, it wasn’t to a mass of supporters fanning out toward the horizon.

Sanders’s first fleeting taste of national fame came, as so many moments in the spotlight do these days, on social media, when he protested President Obama’s 2010 decision to temporarily renew regressive George W. Bush-era tax cuts by occupying the Senate floor and delivering an eight-and-a-half hour oratorical remonstration against inequality and oligarchy in America. The performance was a sensation among denizens of the online left, and later became the basis of a book titled The Speech: A Historic Filibuster on Corporate Greed and the Decline of our Middle Class. But by that time, the Bush tax cuts had been extended and Sanders had returned to relative obscurity, resurfacing only once, to promote the idea of a progressive primary challenge ahead of Obama’s re-election campaign. Democrats rebuffed him overwhelmingly.

It’s not that Sanders’s vision for the country was denied a hearing because it was fringe—promoters of ideas far more extreme are received warmly in the media all the time. Sanders wasn’t on the news often because he was often unable to make news. He was a political independent, for one thing. Moreover, activist progressives like him lacked the numbers and organizational prowess to force their ideas on the Democratic Party the way movement conservatives have done to Republicans for decades.

It took a relentless and phenomenally underestimated presidential primary campaign for his message to finally break through to the masses, and as it turns out the receptive audience was enormous. Over the course of a year, Sanders has hosted dozens of rallies the size of small cities, won 19 caucuses and primaries so far in states large and small (with another expected in West Virginia on Tuesday), and compiled a massive list of supporters, comprising millions of people who together donated north of $100 million to his campaign.