Bernie Sanders’ campaign is a rousing success. He’s drawing huge — sorry, youuuuuge — crowds, he’s smashed expectations for fundraising, and he’s making noise in select polls.
None of which makes him a serious contender for the Democratic nomination. He still trails badly in national polls. And the dynamics of the primary system have shifted in favor of the frontrunner: an underdog can compete in the early states of Iowa and New Hampshire, but then the primaries come fast and furious, and you need a strong national organization (and a youuuuuge amount of money) to stay competitive. Even lackluster frontrunners like John Kerry and Mitt Romney can use their “inevitability” to steamroll their opponents. Hillary generates a lot more enthusiasm than either of those legacy admissions.
So no, Bernie’s not winning the nomination. But he has already won a very important victory: he has shown the potential for game-changing enthusiasm on the Left. After Bernie, the Democratic Party will have a harder time taking the Left for granted.