<P> The religious affiliations of Presidents of the United States can affect their electability, shape their stances on policy matters and their visions of society and also how they want to lead it . Speculation of Thomas Jefferson, Abraham Lincoln, and William Howard Taft being atheists was reported during election campaigns, while others, such as Jimmy Carter, used faith as a defining aspect of their campaigns and tenure to hold the office . Almost all of the presidents can be characterized as Christian, at least by upbringing, though some were unaffiliated with any specific religious body . Protestants predominate, with Episcopalians and Presbyterians being the most prevalent . There has been a single Roman Catholic president, John F. Kennedy . No president thus far has been openly an atheist . However, it has been acknowledged that two US Presidents--Thomas Jefferson and Andrew Johnson--had no religious affiliation . </P> <P> Most presidents have been formal members of a particular church or religious body, and a specific affiliation can be assigned to every president from James A. Garfield on . For many earlier presidents, however, formal church membership was forestalled until they left office; and in several cases a president never joined any church . Conversely, though every president from George Washington to John Quincy Adams can be definitely assigned membership in an Anglican or Unitarian body, the significance of these affiliations is often downplayed as unrepresentative of their true beliefs . </P>

Who was the only roman catholic ever elected president