At the end of his second term, Rye did not seek reelection. He instead ran for the U.S. Senate seat held by John K. Shields. Shields, who had been elected to the seat by the state legislature prior to the passage of the 17th Amendment (which established direct election of senators), had angered President Woodrow Wilson by opposing the League of Nations, and Wilson threatened to endorse Rye. Senator Kenneth McKellar convinced the president to withhold his endorsement in return for Shields' support for the League, however, and Shields defeated Rye for the nomination.