Cry "Wolf!!"
The US and British political leadership have touted many, many "smoking guns", and have lied and forged their way out of any credibility.
That is, if one is rational, one relies upon past truths to trust present statements, and so on.
Bush, Blair, & Co. are so bloodthirsty they would call an empty candy bar wrapper a "smoking gun" if they thought anyone, anyone at all, would believe it.
And some here would.
Arf