It's hard to believe now, when evangelicals and fundamentalists make up the most organized bloc in American politics, but before the Moral Majority a person's churchgoing habits didn't tell you much about how they voted, and politicians weren't expected to make lavish displays of their piety. The notion of church/state separation, now widely regarded by Republicans as part of a devious war against Christianity, was a widely shared principle. Falwell himself once denounced preachers who got involved in governance, though not out of devotion to a secular republic: As a committed segregationist, he decried the work of Martin Luther King Jr, saying, "Preachers are not called to be politicians, but to be soul winners."
Two points. First, before the 1970s, whether a person went to church didn't tell you that much about their voting habits, but where they went to church certainly did. Is the separation of church and state really more imperiled today than it was in, say, the 1920s, when Catholic Democrats and Republican Protestants did battle over whose interpretation of Christian teaching on alcohol should be the law of the land? Or in 1900, when William Jennings Bryan, he of the "Social Gospel", ran for President against William "let's Christianize the Filipinos" McKinley? Seriously?
Second, isn't it a little weird that Michelle Goldberg basically seems to agree with Jerry Falwell's critique of Martin Luther King?