It was clear even before the invasion that the real reason many of the neo-cons wanted to invade Iraq was to bring in democracy at the point of a gun. Many people find the excuses used to cover this real reason abhorrent. (And while most of these are people who opposed the war - some are those who supported the war but still find making an excuse wrong.)
Without getting in to the moral arguments for this, I would like to bring up one observation. Roosevelt made a much bigger stretch before Pearl Harbor in bringing the U.S. in to war against Germany/Japan. And he did this when there was a clear majority against fighting in WWII.
First off, the U.S. Navy was already in a shooting war in the North Atlantic with the Germans having attacked several U.S. destroyers and having sunk one. And the U.S. Navy had depth bombed several U-boats.
In the pacific Roosevelt ordered the USS Lanikai to steam to Malaysia (from the Philippines) so that if the Japanese attacked the British, they would be forced to sink the Lanikai pulling the U.S. into the pacific war.
In hindsight, it was a totally necessary thing for the U.S. to actively fight in WWII and not just supply arms the the British and Russians. It will probably be at least 20 years before we know if Bush's decision was also a very good thing.
But using other excuses for attacking Iraq is not without precedent. And in the case of Roosevelt, it was a necessary step the world needed.
