Vice President Joe Biden and Rep. Paul Ryan were the two candidates on stage at Thursday’s vice presidential debate, but a third character emerged: Joe Biden’s laugh, which didn’t escape the notice of tweeting politicos. (And led, of course, to at least three satirical Twitter accounts: Laughing Joe Biden, Biden Smirk, and yet another Laughing Joe Biden.) Weekly Standard’s Mark Hemingway: “Joe Biden’s laughing through talking about Iran sanctions?” TIME’s Michael Scherer: “Not sure debate cameras have been light tested for Biden’s teeth. Best to watch with sunglasses.” Washington Examiner’s Philip Klein: “Biden’s strategy seems to be to laugh at...