"With the Democratic left-wing demanding a hasty U.S. timetable out of Iraq, Edwards criticized the New York senator for not ruling out that U.S. troops might engage in some combat missions in Iraq if she were to win the 2008 election.

"'To me that's a continuation of the war," Edwards said. "Combat missions mean that the war is continuing. I believe the war needs to be brought to an end.'"

"Edwards' broadside put Clinton on the defensive at a time when she is enjoying a comfortable lead in opinion polls and trying to appear above the fray. But there was no sign that the debate would prompt a major shake-up in the Democratic field."