There are three simple possible reasons the Bush administration decided to invade Iraq:

1) They had conclusive evidence that Saddam had or was very close to having WMD and he was generally a bad guy.

2) Saddam had to be eliminated to reduce threat to the region/US and he was generally a bad guy.

3) Influenced by some very powerful lobby to invade while agreeing that its a win-win for US and other powers and he was generally a bad guy.

As it has been clearly demonstrated by the events after ousting Saddam if Bush administration used any of the reasons above to invade then we need to seriously consider who the hell is running this show!!

What has been done in our name is against Geneva convention and all UN resolutions concerning waging war. They violated Uniform Code of Military Justice, which directs military personnel to obey the "lawful command of his superior officer". For more info see http://www.omjp.org//ArtLarryDisobey.html