A stupid theory from Krulwich at NPR. Yes the south works out, but the rest is a stretch of the most conservative country in the US, and Canada. And the fertile stretch isn't from plankton, it is from much later glaciation. In fact, because of the correlation between plankton and oil, one could easily argue that this explains conservative voting.
Stupid. Stupid. Stupid. Also hat tip to Tom Dispatch for spreading the stupid. What a moron.