I’d post all the ways that government failed New Orleans and Louisiana and Mississippi, but this post on Sploid does so quite well and points out the key insight: the consept of “Homeland Security” over “Civil Defense” has been an unmitigated failure.
Instead of trying to catch every perp who might want to bomb us, we could have prepared for city-destroying-level disasters, hardened the targets, and enabled more robust responses instead of giving privacy-destroying toys to every podunk sherrif’s department in the country who wanted to spy on and beat up blacks, gays, and pot smokers.
The only thing sploid doesn’t cover is the fact that local government in New Orleans and Louisiana could have been prioritizing levees and disaster planning even if the federal government wasn’t there with funds. They could have ignored the federal government’s failure to act in the aftermath. They could have planned for evacuuating the superdome immediately after the storm or getting supplies to it.