In colonial times, and early in U.S. history, the Northern United States, particularly New England, was known for reactionary morality and religiosity. In contrast, the South, prior to the Second Great Awakening, had a reputation as being a fairly irreligious part of the U.S. - most people had marginal attachment to religion and baptism was fairly rare.
In OTL, the roles of the two regions slowly reversed, with the South becoming the religious, reactionary part of the country, and the North becoming the more secular and progressive region. Could this shift have been forestalled? How could we get a U.S. today where the South is known for low support for fundamentalist Christianity, a live-and-let-live morality, and perhaps broad support for progressive economics. Conversely, how could we retain New England in particular as the most religiously devoted and uptight region in the U.S.?