Almost since the moment of his inauguration, former President Donald Trump has been the kingmaker of the Republican Party. In both the 2018 and 2020 elections, Trump-endorsed candidates won almost every Republican primary they competed in. (Of course, many of Trump’s endorsees were already well on their way to victory, but it was still a hot commodity among candidates, serving as evidence of their pro-Trump bona fides. And in several cases, Trump’s support really did appear to influence the outcomes of primaries.) Now that Trump is no longer president, however, one of the big questions of the 2022 midterms is...