Religion and politics, still bedfellows?

I was going to right about conservative views in the south when I stumbled upon an interesting article. Its relatively short but the authors took a survey to find out which ares of the United States were the most religious. They found that "the map reinforces some of the usual stereotypes about the religiosity of the Deep South and the lack of religiosity in the Northeast and Pacific Northwest." Based on the survey it does seem like the southern states are far more religious than those in the north/west. The interesting thing that the article points out this map and the presidential election map from the 2008 election share alot in common.

Its fairly obvious that the darker colored areas are those that seemed to vote Republican while the less religious northern states voted Democrat. The last line of the article is "Religion and politics, still bedfellows." which implies that the two go hand and hand. This means that more religious areas tend to vote Conservative and the less religious areas are Liberals.

Although there is a high correlation between the religion and political vote, I would argue that these two are not related. I can't wrap my head around how being more religious would cause a region to vote one way or the other. My belief is that the similarity is more of a coincidence. The south typically and especially in the 2008 election votes more Republican, not because of their religion but because of their political views. Any thoughts?