Jimmy Carter

 was a president of the United States. He had once been a peanut farmer. (PROSE: The Assassin's Story)

According to the Eighth Doctor, he served in the 1970s and was succeeded by Ronald Reagan. (PROSE: Interference - Book One) His indirect successor from the 1990s, Tom Dering, once speculated that either he or Reagan must have secretly constructed Station Nine. (PROSE: Option Lock)