Victor Davis Hanson has a must-read column in Real Clear Politics on that very subject. (Tip: He doesn't think we should use force.) It convinced me; maybe it will convince you too.
Meanwhile, Daniel Henninger asks:
Carried aloft on the gassy fumes of politics, the congressional Democrats may be overshooting on Iraq. Six months from now, they may wish they had been more temperate. Helped finally by the right U.S. military strategy, the Iraq nightmare might be ebbing. Then what? [snip]Read the whole thing.
This is heady stuff, rolling a president off the field, so heady the Democrats may be allowing their compulsions to make them the one force thwarting a much longed-for military success in Iraq. This in turn could leave the Democratic Party on the wrong side of the most revered institution in American life--the U.S. military. That is, back where they were when Bill Clinton was president. The "we support the troops" mantra will ring hollow if the Democrats are pulling out Army and Marine personnel just as they're gaining on the killers of their comrades.