Inspections Don't Work!
According to the Washington Post:
"Between 1991 and 1998, when the previous U.N. Special Commission on Iraq had inspection teams in the field, under U.N. supervision, Iraq destroyed 817 of 819 proscribed medium-range missiles, 14 launchers, 9 trailers, 56 fixed missile-launch sites, 73 of 75 chemical or biological warheads and 163 warheads for conventional explosives. U.N. inspectors also supervised destruction of 88,000 filled and unfilled chemical munitions, more than 600 tons of weaponized and bulk chemical weapons agents, 4,000 tons of precursor chemicals and 980 pieces of equipment considered key to production of such weapons."

See? What'd I tell ya? Did you notice? What about those last two medium-range missiles and chemical/biological warheads?