"Yeah, I am starting to doubt the existence of WMD in quantities, qualities and capabilities that will justify our pre-war hype. "

Quantity of WMD was not justification. It's unwillingness to give inspectors access to verify. According to the UN inspectors it was "thought" that there were large quantities: large quantities aren't easily disposed of, you can't misplace them, they can be detected even if the were disposed of years later (unless they were properly disposed of, then you need these facilities, and records and eyewitness of this process of getting rid of them, etc). For any world leader it would be required that WMD were verified by inspectors- you can't simply take their word on it (esp Saddam).

You don't need large quantity of this stuff to be a threat to the US- that's the whole friggen idea, small portable quantity could be carried- not by some train of tanker trucks but in one van or car then expose part of some city e.g., New York City. This might only kill 1% of the population (100,000 people) and injure another 1%. What does this do- it TERRORIZES. It shuts down the economy. You don't know when another attack might take place.
You don't even have a "known" enemy. You don't even need to kill 100,000 in one go. If you kill 1000 people at a time, 100 times, people are even more terrorized, and the economy would be non-existant after 100 such attacks. Look at what one stupid sniper did to Washington. It's one thing to have a terrorist attack (the purpose being to send some political message) it's another thing to have a group trying to kill massive amounts citizens- with intention of ending civilization as we know it. Flying a couple planes into the World Trade Center wasn't a message, it was an act of unconventional war.
Now Saddam couldn't win a conventional war, but what about a unconventional one? He wouldn't need to take terrority, actually all he would need to do is get us out of the way. Now, lets look at N Korea, they don't want the US out of the way (cause S korea alone could defend itself, though many would die in the process) N korea wants to make money- selling illegal weapons or having us pay them not to make weapons.
Now, Iran doesn't see the US as a threat to what it wants, so again it's a country that we can work with. Therefore Iraq & Afghanstan were unique threats to the US and the rest of the World- and the terrorists committed to the destruction of the West Culture are also- as long as they have the funding and will to continue this war. So Israel & Palestine are the next main problem we must solve. Israel is now in a different position than it was before Iraq. One value of Israel is that it was one dependable ally in the in a very important region. If we can get Iraq viable and say get a more friendly relationship to say Syria, then Israel "value" is diminished. Which means we got some serious leverage to get Israel to move & if Israel is unwilling to move, it becomes "more" of a security problem for the US, less of a security asset.