A year ago, when New Jersey Gov. Chris Christie served as chairman of the Republican Governor’s Association, stumping for Republicans across the nation, he and Ohio Gov. John Kasich were bosom buddies.

They saw themselves as reflections of each other. Mr. Christie and Mr. Kasich, who have been elected twice by their state’s voters, have little if any daylight between them on virtually any issue of the day, from advocating for lower taxes and less government regulation to hounding teacher unions and gutting public pension plans, among many other topics.

Christie No Longer Loving Kasich

But now that each is […]