Polls show a narrow plurality of Americans oppose the confirmation of Judge Brett Kavanaugh to the Supreme Court. Democrats hope that opposition helps them win back majorities in one or both chambers of Congress in the Nov. 6 midterm elections. But intensity is what matters in politics. Voters in the key states that will determine party control of the House and Senate appear to have turned against the tactics Democrats have used to fan the allegations of sexual assault and other sexual misconduct against Kavanaugh. The reason for the greater enthusiasm of GOP voters to turn out can be explained...