A half-dozen senators fighting for their political lives — and their party’s hold on the majority — in tough races while trying to avoid being dragged down by an unpopular president and the stark reality that second-term midterm elections almost never work out for the side controlling the White House. 2014? Yes — but also 2006, an election cycle that Republicans are increasingly beginning to see as a parallel to this one as the fight for control of the Senate enters its final four weeks. “During that cycle, our guys in Pennsylvania, Virginia, Rhode Island, Missouri, Montana and Ohio could...
