The Puzzle of State-by-State Unemployment Rate Variance - Alpha

National unemployment is high at nearly 9.5%, but some US states are quite healthy!
The WSJ today has an excellent graphic on it:
http://blogs.wsj.com/economics/2010/07/20/most-states-post-drop-in-jobless-rates/

Unemployment Rate at Highest Level in 3 Decades

State-by-State Unemployment Varies a Lot

KEY POINTS TO NOTE

-The Dakotas are at 3-4%!

-The agricultural Midwestern states are low too:
Nebraska at 4.8%, Iowa and (diversified) Minnesota at 6.8%.

-New Hampshire is at 5.9% and Vermont at 6% - these are healthy northeastern states.

-States with failed, subsidized industries (autos in Michigan/Indiana/Ohio) and real estate/casinos in Nevada are crushed:
13% and 14% unemployment in Michigan and Nevada.

For me, the biggest political/economic national problem in the US is JOBS. So I ask: Why is there such a huge divergence between the states?
Among big states, why are TX and NY doing well at 8%, while CA and IL are getting hurt at 12% and 10%?

Few to no economists are studying the divergences, and I think this is a fascinating and very important problem!

Can anyone send me an explanation for these data points?