It was a total local and state government breakdown!
In my opinion the breakdown was in strategy, strategy by the state and specifically by Blanco's husband and his cronies. Something that has not been mentioned in awhile is when Bush wanted to come in and help, Blanco asked for 24 hours to decide and her advisors (meaning her husband and his crooked buds) decided against it because "they (the fed) will want to take over and run everything." That meant the billions of dollars that would flow through there would be in the hands of the fed rather than the Louisiana Democrat operatives.
While Nagin and the behind the scenes operators in New Orleans tried to figure out how to handle the thing to their advantage, and Blanco's husband and his cronies tried to figure out the same, the situation went to Hell. Can we say Nero fiddled while Rome burned?
All the other delays including the Red Cross and FEMA, were efforts by the local Democrats to block outsiders and keep control of the situation, and behind it all was greed.