structural:reformatting, quality:corruption
Campaign for vice president (1920)

Roosevelt's plan for Hoover to run fell through after Hoover publicly declared himself to be a Republican, but Roosevelt decided to seek the 1920 vice presidential nomination. After Governor James M. Cox of Ohio won the party's presidential nomination at the 1920 Democratic National Convention, he chose Roosevelt as his running mate, and the convention nominated him by acclamation. Although his nomination surprised most people, he balanced the ticket as a moderate, a Wilsonian, and a prohibitionist with a famous name. Roosevelt, then 38, resigned as Assistant Secretary after the Democratic convention and campaigned across the nation for the party ticket.

During the campaign, Cox and Roosevelt defended the Wilson administration and the League of Nations, both of which were unpopular in 1920. Roosevelt personally supported U.S. membership in the League, but, unlike Wilson, he favored compromising with Senator Henry Cabot Lodge and other "Reservationists". Republicans Warren G. Harding and Calvin Coolidge defeated the Cox–Roosevelt ticket in the presidential election by a wide margin, carrying every state outside of the South. Roosevelt accepted the loss and later reflected that the relationships and goodwill that he built in the 1920 campaign proved to be a major asset in his 1932 campaign. The 1920 election also saw the first public participation of Eleanor Roosevelt who, with the support of Louis Howe, established herself as a valuable political player. After the election, Roosevelt returned to New York City, where he practiced law and served as a vice president of the Fidelity and Deposit Company.