Congratulations are in order to President Trump and his new running mate, J.D. Vance. Will their combination — and contrasts — prove to be a team that is even greater than the considerable sum of the parts? Mr. Vance has, once he found his footing in the Senate, been a spirited and articulate supporter of the 45th president. He will be the one to watch in a debate against Vice President Harris between now and November.