Sen. Joe Lieberman, the independent from Connecticut, is planning to announce Wednesday that he will not seek re-election, according to two knowledgeable Democratic sources. The move by the former Democratic vice presidential candidate could add even more murkiness to the party's hopes of hanging on to its slim majority in the Senate in the 2012 election, especially coming on the heels of Sen. Kent Conrad's, D-North Dakota, that he will not seek re-election at the end of this term. North Dakota's other Senate seat fell into Republican hands in the midterm election after Democratic Sen. Byron Dorgan announced his retirement....