The Republican Party lost its House majority on July 28, 2017, when Sen. John McCain ended the party’s seven-year quest to repeal ObamaCare. House leadership had done an admirable job herding cats. On the second try, we passed the American Health Care Act in May. Then McCain’s inscrutable vote against the Senate’s “skinny repeal” killed the reform effort.

McCain’s last-minute decision prompted a “green wave” of liberal special-interest money, which was used to propagate false claims that the House plan “gutted coverage for...