Vice President Kamala Harris was detailing her priorities for the campaign during a flight on Air Force Two early last week when she was asked a delicate question hanging over the Democratic ticket: Do voters’ concerns about President Biden’s age mean she must convince them she is ready to serve? “I am ready to serve. There’s no question about that‚” Harris responded bluntly. Everyone who sees her on the job‚ Harris said‚ “walks away fully aware of my capacity to lead.”