that is a political appointment, as the article says. in addition, from THIS article http://www.postchronicle.com/commentary/article_212499.shtml:
(1) It is against the law for any President to order troops into a city or across state lines without a request and permission from the Governor of that state.
John Armor, a First Amendment lawyer and one of my favorite writers, told me, "Federal law prevents the President from sending in the National Guard until the Governor gives the order. It is little known, but the Commanding General of the National Guard in every state reports to the Governor, not the President, until the Governor says otherwise. U.S. military units (regular Army, not the Guard) cannot be used because of the Posse Comitatus law, until the Guard has been authorized."
According to some news sources, the Governor of Louisiana, who knew the levees were weak, who knew that the city had been slowly sinking, and who knew that a major # 5 hurricane was approaching her city, did not call Washington for help.
(2) The Mayor of New Orleans did call for evacuation over a loud-speaker, but did nothing to be sure that the police went door-to-door, followed by transportation, to pick up all those who did not have cars or any ability to leave.
There was no other leadership practiced by the mayor there, as had been in New York City during 9/11 by Mayor Giuliani.
She filed a request with FEMA for disaster assistance on 8/28.