N. inspectors from returning to Iraq since 1998, therefore he may already be close to acquiring said weapons thus cause for the U.S. to stop him before he succeeds.
Upon closer look, this proves the opposite of what is required, that the threat is neither clear nor imminent. All that this indicates is that we simply do not know whether Iraq has developed WMD, whether it will, or when. It is unfortunate we do not seem interested in finding out. The administration does not know whether there is as clear and imminent threat from Iraq, cannot prove one exists, and resists proposals for finding out because the answer might undermine their plans for war.
The administration and advocates for preemptive war deduce a direct; specific, concrete focused at the U.S. threat from Sadaam's criminal record, evil character, and the fact he used poison gas during his war with Iran, and against his own people in the 1980's and the brutal repression he has resorted to since. So if and when he gets WMD he could and would use them against the U.S. or its allies in the region.
This argument ignores certain inconvenient facts. The U.S. supported Iraq in its war against Iran, and turned a blind eye to use of chemical weapons. Never at that time did the U.S. consider the attack on Iran or the atrocities committed under its guise grounds for overthrow. The people who Sadaam brutally repressed were mainly Kurds who the U.S. encouraged to rise up then failed to support. These statements fail in proving what there supposed to, that the threat from Iraq is; concrete, specific, and directed against the U.S. or any U.S. allies.
The administration attempts to prove the threat from Iraq as critical; vital interest face unacceptable harm and danger by repeatedly invoking the memory of 9/11, the war on terrorism, the right of the American people to security against terrifying new threats revealed by the attack, and the duty of the government to provide that security at any and all costs.