I think a levee/dike protection system could have been completed in 5-10 years. The Lake Ponchatrain barrier - about 40-50 miles should have been a priority, since it is already higher than Sea Level. I have seen 40-50 miles of interstate in Texas completed in 2-3 years (see I-290 out of Houston), and that is about the engineering effort required for the same length of levee.
Also see the new Interstate going through Texas - for more trade with Mexico.
Hurrican Andrew occurred during the first Bush administration - and concerns were raised then about New Orleans and a potential flood.
The Mississippi Flood of 1993, during the first year of Clinton's administration, (which did threaten New Orleans) also raised concerns. The necessary studies should have been completed then.
I believe the issue of flooding in New Orleans has been raised every year since then.
Neither the Clinton nor current Bush administration were sufficiently concerned to protect New Orleans, and it is certainly about politics.
Louisiana and Mississippi are both poor states. Both rely heavily on gambling in their economies. Neighboring Texas gets a lot of Federal Highway money. Guess how much I-69 will cost, and guess how much is being spent in Texas.
Interstate 69, a national highway project, will be a new 1,600-mile facility that connects Mexico, the United States and Canada.
http://www.i69corridorstudy.com/ and http://www.i69texas.org/- Bush has his priorities alright.
The war in Iraq has cost nearly $200 billion. At $10 million/mile - 50 miles of protective levee/dike would cost $500 million, and even at $100 million/mile, that is only $5 billion (probably on the high side), compared to the how ever many $billions it will cost now - and the lives lost!
The software to perform such studies has been around for years, and I know companies, which have done this type of analysis, and it could have been done within a year or less.