GOP gains 54th Senate seat with Bill Cassidy's win in runoff
                                
                                
                                    (Newser) -
                                    In what  Politico  calls "Dems' final insult" from Election 2014, Mary Landrieu lost her Senate seat last night, in a convincing defeat that denied a Louisiana political scion a fourth term, gave Republicans a 54th seat, and unceremoniously dumped what  ABC News  terms the "last vestige of Democratic...