As the story goes, first Goldwater and then - more successfully - Nixon adopted a strategy of appealing to white Southern voters dissatisfied with the desegregation and civil rights policies of Kennedy/Johnson. But Nixon's success is hard to assess, since the 1968 election was skewed by the presence of Wallace, and 1972 by the complete debacle of McGovern.
Then, in 1976, Carter got a result very similar to that of Kennedy in 1960. Carter, albeit a Southerner, had a record as a pro-civil rights governor. The narrative just doesn't seem as straightforward as it's often presented.
Watergate irritated some of the Christian values voters who just joined the new coalition, while Carter was simultaneously explicitly pandering to Christians.
