What FEMA does NOT do is to Manage Emergencies.
The problem is that it is a federal agency. Federal agencies are famed for inaction, and FEMA is just following the precedent. If Louisiana had filled out the right forms and submitted them six months before Katrina hit, FEMA would have had something ready. But the suddenness of it all simply floored the FEMA, which is used to operating on a glacial time scale.