Rachel Bitecofer, a political scientist at the Niskanen Center, in Washington, D.C., thinks that most pollsters and forecasters rely on outdated ideas about how candidates succeed. She argues that the outcome has far less to do with the candidates’ ideology than we think it does. Her perspective has been controversial, but in July, 2018, months before the midterm elections, her model predicted the Democratic victory in the House with an accuracy unmatched by conventional forecasters. And it suggests that Democrats should stop worrying about losing, and focus on firing up their voters.