We've come to expect that Bill Buckley puts in the final word:

The question will naturally arise: If we had had proof positive that the weapons did not exist on Iraqi soil, would we have held back the war?

...Whether the war that proceeded was indefensible asks a different question, not one that can be authoritatively answered pending the distillation of the scene in Iraq. If what comes out of the bloody present is a reformed society freed of a sadistic tyrant, bent on a future in which there is, so to speak, separation of church and state, and if such developments inspire a whole region in the direction of civic stability, you will not find presidential aspirants in the year 2008 declaiming about the misleading evidence on which we acted in 2003.

And whether or not that exonerates Bush, it will vindicate the policy of forging peace by liberating nations.