A snippet from this article in Politico called, “The Last Taboo.”
Other presidents were also less than religious. James Monroe is not known to have had any religious affiliation or beliefs, nor is Abraham Lincoln. After his death, Lincoln’s wife reported, “Mr. Lincoln had no hope and no faith in the usual acceptance of these words.” His lifelong friend and executor, Judge David Davis, agreed, saying, “He had no faith in the Christian sense of the term.” This was confirmed by another of Lincoln’s closest friends, Ward Hill Lamon, who knew Lincoln in his early years in Illinois, was with him during the whole Washington period and later wrote his biography. As Lamon put it, “Never in all that time did he let fall from his lips or his pen an expression which remotely implied the slightest faith in Jesus as the son of God and the Savior of men.”
William Taft, before becoming president, turned down the post of president of Yale University (then affiliated with the Congregationalist Church), saying, “I do not believe in the divinity of Christ.” According to a 1908 article in the New York Times, “the report is being energetically circulated that Secretary Taft is an atheist.” Taft did not deny it but continued to attend Unitarian church services. And when he ran against the famously religious William Jennings Bryan, Taft was viciously attacked for his irreligion but still won handily.
These presidents reflected trends in the nation at large. True, the 19th century saw huge religious revivals, but there were also a host of popular speakers who traveled the country raising awareness about free thought. Ernestine Rose and later Robert Ingersoll, called “The Great Agnostic,” were tremendously popular on the lecture circuit. In the early 20th century, the Scopes Trial seemed to put to rest religious protests against evolution. (No one at the time would have guessed the issue would rise again later in the century.) The climate allowed for honesty. To take just one example, in 1910 Thomas Edison was asked by the New York Times if he thought it possible to communicate with the dead. “No,” he responded, “all this talk of an existence for us, as individuals, beyond the grave is wrong. It is born of our tenacity of life—our desire to go on living—our dread of coming to an end as individuals. I do not dread it though. Personally, I cannot see any use of a future life.” A public figure could speak of a rationalist, naturalist understanding of humanity and the universe.