Sen. Mark R. Warner (D) is bringing in some heavy artillery in favor of his campaign. Former U.S. senator John W. Warner, a five-term Republican who retired in 2009, is appearing on television in support of his Democratic successor. “In Congress to get things done you gotta have the guts to cross the aisle and reach bipartisan agreement,” John Warner tells the camera. “That’s what I did, that’s what Mark Warner does today. While we come from different parties, we both believe in putting Virginia first. I know Mark Warner. He’s decisive, experienced and has courage.” The end of the...