The Gov. did announce a state of emergency as the Mayor did call for immediate evacuation there was enough time to get troops and people down there to IMMEDIATELY policing and holding the city safe.
If the blame was to be pointed then the Gov. and Mayor are highly likely to lose their jobs but the mayor did order evac and then when poor people didnt want to go he said go to the atsrodome... but he had not prepared that place for them he just suggested it be safer than their houses, he neglected 10,000 people not wanting to leave. Bush will only get a low opinion poll and suffer in the short term, but Bush's reaction was disgusting and slow, true the law states that feds can't come in unless invited, they were invited and they should have been READY, Bush knew the scale of this and he should have had the people ready in choppers and planes and cars trucks whatever and ready to say "GO GO GO" as soon as that call came through.
How long did it take to get FEMA or National Guardsmen (the ones that Bush has not sent to Iraq) etc take to get there and make a difference.