“Honestly, every time I hear you I feel a little bit dumber for what you say.” Nikki Haley’s put-down of Vivek Ramaswamy was perhaps the closest thing to a zinger in an otherwise messy Republican primary debate in which Mike Pence’s jokes bombed, Chris Christie’s “Donald Duck” jibe fell flat and Ramaswamy suffered second album syndrome. It also came as the only woman on stage finds momentum in her effort to displace the faltering Ron DeSantis, governor of Florida, as the party’s leading alternative to Donald Trump. After last month’s first debate, where she provided a dose of realism on...