I don't know if its Katrina but something is going on down LA and MS way.  The Hastert seat in IL is awesome but understandable.  I think there was an 8pt swing from 06 to the special.  Nice.  Good news for Dems but that kind of swing happens dozens of times in every election.

Now in LA and MS they were both over 50 point swings and that is a big deal.

I am deranged and obsessive so I have compiled a massive spreadsheet of how every state has voted in every election and then normalized the margin in each state to the overall margin.  What jumps out at you when you do this is how there are long periods of static and then regions explode across party lines (the South jumping in 1968 comes to mind).  These are the great realignments we are talking about.  50+ point swings are extremely rare and don't really happen for one election cylce.  They stay around.  Is it Katrina? Is it gas prices like Ken's suggests? Is it some other variable we are missing?  I dunno.  But anyone who thinks we are gonna redo 2004 and see who can steal/suppress the most vots in Ohio just doesn't get it.