In truth, the Democratic and Republican parties are two of the most internally democratic parties on the planet. Yes, in the past their systems were far more closed, and presidential nominations were determined by delegates at a convention far from the influence of voters. But now anyone can run in a primary, and party insiders have lost control. In other democracies, primary elections are uncommon, and even where they occur, the requirements to vote in them are high; participants may have to pay dues, for instance. That Sanders, an independent, thrived in two contests shows the party’s openness, not its rigidity.