Mitt Romney and Josh Hawley, polar opposites in today’s GOP, agree on one thing: Donald Trump’s status as Republican kingmaker. After the former president’s endorsement of a former critic rocketed J.D. Vance to the GOP Senate nomination in Ohio, the two senators can’t help but see things the same way. Hawley (R-Mo.), who led Trump-backed election challenges in the Senate last year, observed that “he’s the leader of the party, that’s clear … If he decides to run, he will be the nominee.” And while Romney twice voted to convict Trump in impeachment trials, speaking out against him more than...