Not that it matters for this discussion, but blue laws don't prohibit only the sale of alcohol; it's much more broad than that. I'm from TX, and when I was growing up you couldn't buy much of anything on Sunday except food. That has changed for the most part, but you still can't buy hard liquor (however, you can't buy hard liquor after 9 pm either, regardless of the day of the week).
More to the point, I don't necessarily think gambling laws follow a particular region. Yes, the South tends to be socially more conservative, but look at the states mentioned above which have restrictions - Connecticut, Arizona, Illinois, Delaware, Maryland.....
It's just what what agenda the local politicians have at the time. |