What worked then should work now. It is past time to hide under the covers of "the rule of law" and "states' rights", much less the phrase, "help is coming real soon". The looters and snipers must be suppressed without mercy, and the remaining population of New Orleans must be entirely and quickly evacuated under the strict supervision of the regular military and Federalized National Guard.
Get it through your skull: it is illegal for President Bush to usurp the clear authority of the governor in this situation, and use the U.S. military for law enforcement - that includes the Coast Guard.
If you don't like that, press Congress to change the Constitution, and the law.
FEMA and Coast Guard are considered Law Enforcement, not troops.
There have been acts of Congress since to ensure that what Eisenhower and Kennedy did cannot happen again, alas.