[img]http://d.yimg.com/a/p/ap/20100202/capt.3627ebf40903421d91ee07fd6a422dae.obama_nhpm116.jpg?x=130&y=86&q=85&sig=k2EEARtdz_GUoCeC6PF6_A--[/img]AP - President Barack Obama unleashed bare-knuckled criticism against opposition Republicans on Tuesday, using some of his toughest language yet to paint them as electoral opportunists willing to switch positions at will to score points with voters.