After signing the landmark civil rights bill into law in 1964, President Lyndon Johnson made a famous prophesy about the future of the Democratic Party: “We have lost the South for a generation.” Since 1956 (and only rarely before), the Republicans—the “Party of Lincoln”—had struggled to win any electoral votes from a state south of the Mason-Dixon line. Then the G.O.P. nominated Senator Barry Goldwater, who had voted against the civil rights bill and proceeded to win Mississippi, Alabama, Georgia, Louisiana and South Carolina. LBJ’s predication was proving out, which it did again in 1968, when Richard Nixon inaugurated what became known as a “Southern Strategy.” Democrats won only Texas among the states of the Old Confederacy—and in 1972, lost them all.

The next presidential election, though, the Democrats threw a curveball: they nominated Jimmy Carter, the former governor of Georgia—and pundits began talking about the Republicans’ Southern Strategy as thing of the past.

Politics, however, is rarely so simple. One of the things that made Carter such a remarkable politician in 1976 was his ability to attract the loyalty of so many different classes of voters—some of them from constituencies traditionally opposed to one another. President Gerald Ford’s adman Mal MacDougall tells a story in his campaign memoir about the first strategy briefing he attended with Ford’s brilliant and innovative pollster, Robert Teeter. One of his innovations was something called a “perceptual map”: a series of acetate sheets with dots printed upon them, each sheet representing a different voting bloc, each point a surveyed voter.

Teeter began slowly laying sheets on top of one another:

Thousands of little dots began to cluster around Jimmy Carter. Blue-collar workers started clinging to the Carter circle. Intellectuals gathered around him. Catholics and Jews…Blacks and Chicanos smothered him with their dots. People who care about busing dropped at his feet. People who were for gun control sided with him as well. Conservative women kissed his feet. Liberal women hugged his head. Environmentalists swarmed around him. The Rich touched him. The poor clung to him.

The Ford people emerged terrified; terrified, too, about a new political constituency that Carter, a devout Southern Baptist, was bringing to the table. Evangelical Christians, traditionally chary of getting involved in partisan politics. “It could be the most powerful force ever harvested,” Teeter said at that meeting. “They’ve got an underground communications network. And Jimmy Carter is plugged right into it.”

Then history, as it likes to do, threw a spanner into the works.

That summer, for a magazine article, Carter had sat for a series of wide-ranging interviews that formed perhaps the richest document of a presidential nominee’s thinking in the history of American electioneering. The candidate was strikingly self-reflective, unusually open in taking on sacred cows, frank in acknowledging America’s faults. He aired his self-doubts, his fears—but also, bracingly, his lack of fear regarding one subject in particular: the possibility of his own death by assassination. The reason, he said, was his Christian faith—which led to a long and searching theological discussion that culminated in an observation, in explaining the Christian concept of sin and redemption, that God had forgiven him even though he had committed “lust in his heart.” And because it appeared in the November issue of the soft-core pornography publication Playboy, Carter’s reference to sex became all anyone could talk about.