Story highlights Sanders' most loyal supporters are now convinced the system is rigged, setting up a collision course for Democrats

Winning over Sanders supporters is critical to Clinton's campaign

Philadelphia (CNN) Three words are hanging over the final days of the Democratic presidential race: Bernie or bust.

"When you say Bernie or bust, that means if we don't get Bernie, we're just not going to automatically vote for the demon because you're saying the devil may be there," said Billy Taylor, who is organizing a coalition of Bernie Sanders supporters to protest at the Democratic convention here in July.

Sanders has inspired a movement, but it's unclear whether he can control it. Or if he wants to.

After the final wave of states vote next Tuesday, Sanders has one decision to make. His supporters have another. And many insist they will not fall into line behind Hillary Clinton.

"You can't expose the corruption of the political system and then expect us to get behind that same political system," said Gary Frazier, a leader of a group called Black Men for Bernie, who is also organizing Sanders supporters here in Philadelphia.

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