Its much more likely that WMD will be used against rebel populations and US force bases in northern and southern Iraq where the world outcry will be less and the range of delivery vehicles greater.
Last, the key is the oil and its cash flow. If we cut it off or control it, then his Russian and French apologists shut up and get in line. Even the most loyal mercenary thugs know when their isn't another paycheck. They'll hang his beaten and bloody body from a lamp post for an appropriate cash reward and amnesty.
No weapons of mass destruction will be used by Iraq until Saddam is finished, and then they will be hand-delivered against the US civilian population.