This whole debate is pretty pointless, and reminds me of people who say the Vietnam was was a failure because the Soviet Union ended up collapsing. They like to look at effect without looking at the causes. What would the World today look like had the US not stepped up and lost 50,000+ folks in Vietnam? It certainly would not look like it does today.
So, taking Bushes out of the equation and focusing on facts, let's look at what the World would be like without US action in Iraq. Hussein's stated goal for decades was to unite the Middle East as one massive Arab state, with himself as the leader (of course.) With total control of the area, and a good chunk of the World's oil supply, he would be virtually omnipotent. The virtually comes into play because to be truly omnipotent you have to discourage attacks on your power through three means: Political, economic, and militarily. If he can ruin the economy of virually any country, he's got the first two locked down. The only way to really dissuade attacks militarily is to have the trump card - WMDs.
In order to take control of the Middle East, you have to first control Mecca, which is in Saudi Arabia. There's no way to take Mecca without taking Saudi Arabia, and no way to take Saudi Arabia by coming in from the North. The Saudis would resupply through the ports of Jeddah and Jubail and push the Iraqi forces back to the north. So, Hussein needs to come in from the north, and also hit Jeddah and Jubail, then come at Riyadh from all sides. To do that he needs to have a decent naval force, and in order to support that force he needs deep water ports, which he does not have... but Kuwait does.
So, he invades Kuwait and siezes his deep water ports. The French continue to sell him the ships that he needs, and after a couple of years he has enough ships to invade, and the political, economic, and military resources to cause any opposers to back down. He takes Saudi Arabia by force, and the Gulf States fall into alignment with him. He can then use his leverage to force bigger countries like Jordan and Syria to come aboard to, as semi-independent states at first and later as puppet states. From this position, Hussein has the governments of Germany, France, Japan, and many other countries bowing to his demands or else he'll wreck their economies. That's plan A.
Plan A fails, and now he needs plan B. His military is devastated after 1992, and he lacks the bucks from oil sales to rebuild it. Even worse, his patron, the Soviet Union, picks the same time frame to fall apart, so there's no more weapons Wal Mart to give him the best prices on tanks and fighter jets. If he's going to achieve his life-long dream, the only he's going to do it is by using WMDs to intimidate the other countries into falling under his control. With no real interference, he develops his first nucs, and threatens Saudi Arabia with them. He leverages Islamic, nationalistic, and socio-economic factors in the country to overthrow the House of Saud and he takes over. And as Saudi Arabia goes, so goes the other Gulf States, and Plan A is back on track.
Could Hussein attack us militarily? Hell no! But he could sure attack us economically and do far more damage. And what help would we get from our "allies"? The same folks who were willing to turn their backs on us and support a murderous dictator because he was selling them cheap oil and buying products from their industrial base. If Russia, Germany, and France were willing to turn their backs on the US for a few million rubles or euros, imagine who would turn their backs on us if he threatened to cut off all their oil.
- get used to it.