A somewhat bitter U.S. Rep. Barney Frank said today he will not seek re-election in 2012 in a move he said was triggered by redistricting that left him with too many new constituents to serve as a “lame-duck” legislator. “There are too many constraints,” Frank said about his life as a politician and the energy it would take to meet new voters so late in his tenure. “People are skeptical about incumbents,” he added. “There was also this — I don’t like raising money.”