Interesting (but not unexpected) comments about Iraq. But the original question regards Bush's noble cause, if any. In 2000 when he was appointed President by Scalia, et. al., W's primary goals were dismantling federal regulation enforcement and cutting taxes. The WTC attacks only gave him the opportunity to declare himself emperor, which he could not resist.
But remember, he cut taxes AFTER invading Afghanistan, so this must be his noble cause for no fiscally responsible leader would do so knowing that the country was gong to war. He would ask the country for shared sacrifice instead. The only universally shared sacrifice in the country is higher gas prices.