Why is Iowa so Democratic?

[White Cloud]

I have always wondered why the state of Iowa is so heavily Democratic. Not only in presidential races, but on the Congressional level and in party registration as well. Dems and indies both outnumber Republicans on the voter rolls in Iowa. Three of their five Congressional districts are held by Democrats (who all won re-election yesterday in a year when so many other rural Dems in the Midwest and South went down).

On the presidential level, Iowa has been a good Democratic state since 1988, only failing to go Dem in 2004 and only by 1,000 votes. Obama did well there, you could say the state "made" him. And yet, if you look back at presidential races in Iowa before 1988, it was basically a strong Republican state. Even Carter couldn't win there in 1976. Kennedy got crushed in 1960.

It seems like something changed very dramatically in Iowa politics around 1988 that pushed it very far left. Is that the case? What is going on in Iowa? Why is Iowa so Democratic compared to other prairie states like Kansas, Nebraska, and the Dakotas? It's not really an urban state, so it can't be attributed to urban minority voters. It doesn't have a lot of the ethnic voters that you might find in the urban areas in Minnesota, Wisconsin, Illinois, and Michigan.

The thing that I find fascinating about Iowa is that Democrats, even national-level Democrats like Bill Clinton and Barack Obama, tend to do very well in rural farm areas that are almost 100% white. You just don't see that in other "heartland" areas, definitely not in the rural South or the Plains. If you look at the 2008 county map, Obama won almost every county in the northeast quadrant of Iowa, and a lot of those counties are very rural.

So what is it about Iowa that makes it so Democratic?