The last man standing in last year’s race for president on the Republican ticket has some stern advice for President Donald J. Trump, the mega-sized outlier candidate who defied political gravity by thrashing 16 Republican wannabe candidates with deadly mocking tweets, bombastic statements and finally, and worst of all, more votes.

Ohio’s term-limited chief executive, John Kasich, has won the hearts of many—curiously, many of them Democrats—for not lining up behind Trump as many former anti-Trump Republicans did after the New York billionaire became the GOP’s presidential nominee. On the outs with Trump world after dissing him in Cleveland by not […]