Saddam was a growing threat. He had bypassed much of the sanctions through the corrupt UN Oil-For-Food program and was ready to take his WMD reasearch out of mothballs as soon as his economic allies (France, Russia, China, etc.) eliminated the last of the sanctions. The now 20/20, after going into Iraq, CIA report on Iraq WMDs shows that Saddam could have had weaponized mustard gas in as little as 6 months as the nastier stuff not much longer after that. The reason why Saddam is the most dangerous with WMDs than the others in the Axis of Evil is because he has used them on enemies both foreign and domestic and shows no sign of stopping in the future. Saddam was actively seeking organizations to hurt the USA. From the overall war on terrorism, Iraq was ideal to attack because nobody liked Saddam and Iraq was located in the virtual backyard of the middle east where the terrorists hide in the civilian population of surrounding countries. Saudi Arabia or even Iran are unrealistic targets because they have far more support than Saddam did. By invading Iraq, terrorists were drawn from their safe havens behind civilians in surrounding countries to Iraq like moths to the flame. In Iraq, they had to concentrate, and a concentrated enemy is what our military is best against. Past failed strategies of bombing from afar only grew popular support for extremism and gave them all the time in the world to plan 9/11 and other attacks. Taking Iraq took the initiative away from the terrorists, and they were forced to react to us instead. Taking Iraq also removed a major supporter of Hamas as evidenced by the warehouse full of manufactured suicide vests found in Iraq during the invasion, not to mention all the Palestinian terrorist training camps. The successful overthrow of Saddam also caused two other dictators to change. Libya gave up its nuclear weapons program because of the invasion, and Syria removed its soldiers from Lebanon for the same reason. It was a good thing too because Libya was closer to nukes than anyone thought, and if Syria still had soldiers in Lebanon during the recent Israeli-Hezbollah conflict, the conflict would have spread to Syria and then to Iran and beyond.
By facing Al Quaida man-to-man, our soldiers have revealed Al Quaida's true savagery. It's popular support among muslims has evaporated similarly to how the KKK's support evaporated in the USA when it was revealed to be a worshipper of murder and savagery rather than a defender of the faith. And there is a rare person who misses Saddam.