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His base is energized and pretty much self-organizing a grass roots campaign. They will get people to turn out to vote in the primary based on this enthusiasm.
Numbers don't lie. He isn't winning in the polls and while he is certainly a worthy candidate, his extreme left views are going to limit those who will vote for him. Plus, Hillary killed it in the debate last night.
The primaries were rigged
Hillary is currently polling significantly higher than Bernie overall
Hillary Clinton could have sudden health related issue that scares voters away.
However, this is very unlikely.