As former House Speaker Newt Gingrich prepares for a likely 2012 presidential bid, he's slammed Pres. Obama's recent decision instructing the Justice Department to discontinue enforcement of the Defense of Marriage Act, which defines marriage as a union between a man and a woman. Gingrich said Obama's decision is unconstitutional and suggested he could be impeached for his decision, though a spokesperson for Gingrich quickly backtracked on the statements afterwards.