Patrick Healy, the deputy Opinion editor, hosted an online conversation with the Times Opinion columnists Ross Douthat, David French, Michelle Goldberg and Bret Stephens to discuss Donald Trump’s choice of J.D. Vance as his running mate — why Mr. Trump picked him, how Mr. Vance could help the ticket, what’s surprising and unusual about the vice-presidential nominee, and what if anything worries our columnists about Mr. Vance. Patrick Healy: The answer to one of the biggest questions of the...