In the past week the situation in Iraq has taken a dramatic turn for the worse. While we may have differed on how we went to war, Americans of all political persuasions are united in our determination to succeed. The extremists attacking our forces should know they will not succeed in dividing America, or in sapping American resolve, or in forcing the premature withdrawal of U.S. troops. Our country is committed to help the Iraqis build a stable, peaceful and pluralistic society. No matter who is elected president in November, we will persevere in that mission.