Zito argues that many Americans are religious while Democrats are correctly seen as indifferent or even hostile to religion. She writes of 2006, which she identifies as a turning point:
Exit polls showed Democrats “did well among their core constituencies; compared to 2002, they received increased support from Jews, the religiously unaffiliated, infrequent churchgoers and those who never attend religious services.”In the short to medium run, Zito is likely correct. Being seen as somewhat hostile to faith is still a problem in this nation. She doesn't even cite Obama's "they cling to guns or religion" faux pas.
In other words, Democrats were hugely successful across the country by solidifying their base. In the process, they have pushed away religious voters not simply by ignoring them but by actively repelling them with accusations of bigotry and backwardness.
In the longer run, if American culture evolves in the same directions as those of first world nations elsewhere, being post-religious may be a plus for Democrats. Already most natives of Europe and Japan have left religion behind.
The churches of Europe are largely museums-in-all-but-name, in use mostly for ceremonies of marrying and burying. Polling suggests the U.S. is moving in the same direction, albeit more slowly. Already "none" is one of the largest categories of American response to the question of religious affiliation.