Donald Trump is securing his grip on the Republican Party less than three months before the midterms, with GOP primary voters surging to the polls in Wyoming to oust his most vocal GOP critic, scores of nominees for state and federal offices amplifying his false claims and bellicose rhetoric, and many prominent party figures echoing his evidence-free attacks about the FBI search of his home. Rep. Liz Cheney (R-Wyo.), Trump’s staunchest Republican opponent in Congress, lost her primary Tuesday in a landslide to Harriet Hageman, whom the former president endorsed with the sole mission of dislodging Cheney. The race attracted...