What president had the codename “The Deacon”?

James Earl Carter, whom Forrest Wickman argues in Slate was America’s most religious president:

It’s impossible to know the contents of a man’s heart, but historians who study the religious lives of the presidents point again and again to the words and deeds of James Earl Carter Jr. The Georgia Baptist set a new standard during his 1976 presidential campaign when he described himself as “born again,” and he was frank about his religious beliefs throughout his presidency. While in office, Carter attended church wherever he went, even while on the road, and continued to teach Sunday school when at home. He prayed daily and read the Bible, and when he wasn’t reading the Bible he read theologians like Reinhold Niebuhr. Like Romney, he also knocked on doors as a missionary, addressing potential converts by saying, “I’m Jimmy Carter, a peanut farmer. Do you accept Jesus Christ as your personal savior?” Since his presidency he has continued his Christian mission on annual trips for Habitat for Humanity, and when he accepted the 2002 Nobel Peace Prize, he spoke of Jesus Christ as “the Prince of Peace.” His Secret Service codename was “The Deacon.”

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