Sen. Joe Lieberman of Connecticut - Democrat to Independent: Joe Lieberman, the junior senator in Connecticut, holds positions that do not conform to one party. After losing the Democratic primary to newcomer Ned Lamont in 2006, he opted to run as an Independent. His campaigning for Republican presidential candidate John McCain in 2008 put him at sharp odds with Democrats, as did his rejection of the Medicare buy-in plan during the health-care debate. He caucuses with the Democrats. Lieberman is acknowledged here at a banquet of the American Israel Public Affairs Committee (AIPAC) annual policy conference in Washington on March 22.