The former Senate Majority Leader, now a noted peacemaker, may be tapped to help lead the party's strategy on a new high court nominee The battle on Capitol Hill over filling one, possibly two, U.S. Supreme Court vacancies is heating up fast. Faced with a high-powered lineup of GOP tacticians and advisers, Senate Democrats are now working to assemble their own team. One key person under consideration to lead the effort, several Democratic sources tell BusinessWeek Online, is former Democratic Senate Majority Leader George Mitchell of Maine, chairman of the board at Walt Disney (DIS ) and chairman of law...