Before the rise of the religious right in the 1980s, most politicians kept their faith to themselves. In 1945, for example, President Harry Truman wrote: “I’m not very much impressed with men who publicly parade their religious beliefs.” After his election in 1953 President Dwight D. Eisenhower joined a Presbyterian church, but when he heard the minister was publicly boasting about his new member the general commanded, “You go and tell that goddam minister that if he gives out one more story about my religious faith I will not join his goddam church!” John F. Kennedy discussed his Catholicism only when forced to do so by critics during the 1960 presidential campaign. In a 1964 interview with the Baptist Standard, President Lyndon Johnson explained, “I believe in the American tradition of separation of church and state which is expressed in the First Amendment to the Constitution.” Richard Nixon was famously a Quaker, but what he practiced can best be described as religious expediency—whatever worked politically. Gerald Ford called his religiosity “very personal” and wrote, “I am most reluctant to speak or write about it publicly.” Even the openly evangelical Christian Jimmy Carter prioritized his piety below that of most political issues.
Source: Religion Is Disappearing. That’s Great for Politics. – Michael Shermer – POLITICO Magazine