Now, now. Hansie Blix and the Beeb have already reported that enough WMDs haven't yet been found to indicate that there are WMDs in Iraq.
So, what quantity of WMDs must be found before we can consider WMDs to have been found in Iraq? Simple.
X+1
Where X is the quantity that have been found.
Don't forget the multiplier 0, for chance Saddam would have actually used them and the second multiplier 0, for their effectiveness.