Democrats nearly lost their majority in the House on Nov. 3, and their post-election recriminations show the reason. They think their problem was their packaging instead of their policies.

Democrats have already lost eight seats net and could lose as many as 13 after the counting ends. They lost two in South Florida, at least two in California, and here and there across the country in places they had gained in 2018. They failed to pick up seats in Texas, Ohio or Florida, which they had targeted. We also count some 26 seats...