"But when the dust clears, someone's going to have to ask the politically charged question of whether the response was slowed down by the fact that such a large percentage of America's National Guard has been shipped overseas."

Ask away. It isn't a lack of available guard, it is a lack of leadership at the local and state level coupled with a lack of available communications. If this were just about a city, basic services disrupted in nearby communities would be up and running to act as staging venues. As it is, you could put 40 thousand National Guard personnel in the area, but they couldn't communicate with each other and local authorities, and even if they could, given that there is nothing available as support for those people, it wouldn't be more than a couple days before those people would be just as desperate for basic life support systems as those who they are trying to help.

New Orleans as it was will never be again. And it shouldn't be. The costs to clean up the destruction will be huge. Reconstruction costs of the same area would be prohibitive, and stupid, because this will happen again. They just got lucky it took this long for it to happen the first time.