Protestant theologian C. S. Lewis subscribes to the idea of a cosmic battle between Good and Evil. According to this idea, the Forces of Good have for some reason chosen us--humanity--as the front and final line of defense in this battle.
Developing the military metaphor, Lewis proposes that the faithful are not tested by misfortune as a punishment for their sins, but as a "reward" for their faith. Just as you train your troops hard, so that they will perform well on the battlefield, so also God puts the faithful through difficult tests, so that they will be strengthened for the even harder battles ahead. And just as you would select your most elite units, your most battle-hardened veterans, for the most dangerous and important missions, so also God often chooses those who have suffered greatly to experience even greater suffering.
The reward for faith in times of trial is not a time of peace--not in this world, anyway--but rather even greater trials and even greater tests of faith.
I'm not saying Lewis is right. It could be that we are in the grip of the forces of Evil, and that our suffering comes at the pleasure of the Devil. Or there could be no such thing as "good" and "evil", and what the religious believe are trials of faith are really just the result of random chance.
But if Lewis is right, could it not be that Pat Robertson has it all wrong? That Katrina was not a punishment for New Orleans' sins, but a test of strength and a training exercise for its faithful? A recognition of the great work they have done, and a new battle given to God's Own Combat Veterans?
Maybe it's not about what New Orleans (or the country as whole) has done wrong, but rather a recognition of all that has been done right, in preparation for even greater challenges, even greater victory, and even greater glory.
I'm just saying.