I think it's probably part of the cause, but not the ultimate answer. What really strikes me is that the days of feed sack dresses and barefoot kids picking cotton and baling hay all summer is within the living memory of many people in the red states. Those memories are of making a living under incredibly hard conditions, and doing it as a family, doing it almost alone.

People in the blue states endured equally challenging issues, but the population was often concentrated more in small towns or urban areas. In those places it was industry that held sway. To make dangerous and lethal situations better, people joined unions-- and the help and protection of the unions is within the living memory of many people living in the blue states. We get emotional about the dangers of the coal mines and the help of the unions here, the same way people in red states get emotional about the memory of their grand parents being put off the family farm because they couldn't come up with money to pay the note on the tractor, or some such thing.

Anyway, the group approach became more popular and accepted in blue states. People in blue states experienced the benefit of organizing, and embraced a social (even socialist) orientation that is anathema to the farmer and rancher.

While many of causes of the red/blue divide are historic, you need to remember that they have been exploited for political gain. Remember Nixon's Southern Strategy. He looked at the racist buttons he could push among southern voters and he pushed them, and it worked. As I understand Obama is the first president to move beyond that approach and to win.

Above all, it seems to me that the only way we can move beyond the divide is through compassion for past pain and feelings of betrayal.