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. John F. Kennedy was the first Catholic president and Joe Biden, the current president, is the second. There have been at least four nontrinitarian presidents. No president has openly identified as atheist.