Eight weeks ago, Liz Cheney’s colleagues struck her down—and made her more powerful than they could have possibly imagined. They did so, if the media was to be believed, by inadvertently thrusting into her hands a new megaphone to broadcast her anti-Trump message. Around the same time, former Trump administration official Miles Taylor and dissident 2016 presidential candidate Evan McMullin announced a group of disgruntled Republicans who threatened to form a new third party if the GOP failed to expunge the stain of Trumpism. Despite the hype they received on cable news, neither Cheney’s nor Taylor and McMullin’s efforts have...