People question the war in Iraq. They don't like the idea of our going to war unprovoked. They thought it might have detracted from the war on Terror. They wanted proof that there were WMDs. They don't believe in the rationale that we attacked to evoke a regime change for the stability in the region.
Other people support the war. They like the positives that came out of it. They believe that the world is safer now that a dictator has been removed, and don't understand why opponents don't see it.
The President certainly announced prior to the war that Iraq had to sever its ties to terrorism and did comment on the peace of the region, but in more than one address, the primary rationale for the war was the insistance of WMDs in the country.
Here are a couple links that I've found detailing what was said before and during the war that causes such confusion and divides the country. I leave it to you to determine the probative value and prejudicial effect.
Click here, here, here, and here.