I don't think it is practical to assume the government at the local, state, or federal level could evacuate that many people in a short period prior to the hurricane. The people were offered shelter in the most structurally sound facilities available, that's the best that could be done. True, the government was not prepared for the aftermath. I'm sure they had intentions of evacuating everyone in a timely manner, but the immenseness of the storm (Mobile to beyond New Orleans, with hurricane force winds well into the interior of Mississippi) created a impossible situation in terms of providing immediate relief. The situation in New Orleans (gunfire, accessibility etc.) combined with the geographical size of the destruction, prevented non-government groups from providing the level of relief they normally are relied upon to provide. many were spread thin and not allowed to go into New Orleans. The only arm of the government that could handle such an evacuation effort is the military, and I can understand the reluctancy to immediately declare martial law until all else has failed.
