[154]
During his presidential candidacy, Jackson relunctantly ran for one of Tennessee's U.S. Senate seats. William Berkeley Lewis and the other U.S. senator John Eaton, who were Jackson's political managers, convinced him that he needed to defeat incumbent John Williams, who openly opposed Jackson. The legislature elected him in October 1823.[155][156] Jackson was attentive to his senatorial duties. He was appointed chairman of the Committee on Military Affairs, but avoided debate or initiating legislation.[157] He used his time in the Senate to form alliances and make peace with old adversaries.[158] Eaton continued to campaign for Jackson's presidency, updating his biography, and writing letters under a pseudonym that were quoted in newspapers around the country and so popular that they were reprinted in pamphlet form—Jackson himself had a part in their composition.[159]

1824 election results
Democratic-Republican presidential nominees had historically been chosen by informal congressional nominating caucuses. In 1824, most of the Democratic-Republicans in Congress boycotted the caucus,[160] and the power to choose nominees was shifting to state nominating committees and legislatures.[161] Jackson was nominated by a Pennsylvania convention, making him not merely a regional candidate from the west but the leading national contender.