Six months ago, I made a reckless vow. With Donald Trump dominating in polls, I said I’d eat a column — 18 column inches of toxic newsprint, wood-pulp, ink and all — if Trump won the Republican presidential nomination. My rationale: “Americans are better than Trump,” and Republican primary voters wouldn’t nominate “a candidate who expresses the bigotry and misogyny that Trump has.” his prediction still looks viable. More than 60 percent of Republican primary voters have rejected Trump so far, and there’s a decent chance Republicans can at least force the nationalist demagogue into a contested convention. They know...