Based on your love of conspiracy theories...
you could be shown a video of Saddam touring a WMD plant filled to the brim with weapons and you wouldn't believe it. You've already discounted video of bin Laden admitting to taking part in 9/11. I really doubt anything would constitute proof in your eyes. However, it really doesn't matter one bit whether you are convinced or not. Bush doesn't have to get clearance from you before acting. Thank goodness for that, too.