Trump’s endorsement power keeps saving the wrong Republicans

For a decade, not one lukewarm Republican incumbent senator or governor has lost a primary and been replaced by a more conservative challenger under Donald Trump’s leadership of the GOP. That changed Tuesday night.Four-term U.S. Sen. John Cornyn (R-Texas) did not merely lose to state Attorney General Ken Paxton. He got routed by 28 points.The Paxton endorsement and Cornyn’s defeat should have marked a turning point in Trump’s political strategy. Instead, they look like the high point of the cycl...