Liberals used to occupy the moral high ground in American politics. Operating from a Christian ethic of generosity and kindness, Christian Democrats in the highly Christian and democratic American culture of the late 1950s and early 1960s succeeded in making conservative Republicans look like nothing but so many selfish churls.

Then several things happened. First, television ownership became widespread in the late 50s. Nearly everybody, even the working poor, had a black-and-white TV. With this c...