For Trump, May Could Be the Cruelest Month

If you doubt the power of Donald Trump’s endorsement, look no further than the Ohio Senate race.
Since April 15, when Trump backed J.D. Vance in the Republican primary, the venture capitalist and author of “Hillbilly Elegy” has zoomed to the top of the public polls. Vance jumped from 11 percent of likely voters in March to 23 percent now, according to Fox News.
The real test of Trump’s party boss mojo, however, is fast approaching: actual elections, beginning with Ohio’s on Tuesday. Trump has endorsed candidates in at least 40 Republican primaries that...