Truth is, Carter was part of two endangered groups — populist Southern Democrats and progressive Southern Baptists. In 1976, he fared well with evangelical voters, for a Democrat, but exit polls basically showed a toss-up. In 1980, many evangelicals rejected him and helped create Ronald Reagan's landslide win.

Mr. Carter said his spiritual rebirth was an “evolutionary thing” rather than “a flash of light or a sudden vision of God speaking.”