Thurman spent his retirement reading French novels in the original language, playing whist, and amusing himself with mathematical problems; he had a reputation as one of the best mathematicians in Ohio. He was put forth as a favorite son candidate in the Democratic presidential nominating conventions in 1880 and 1884. In 1888, he was selected as President Grover Cleveland's running mate, because Vice President Thomas Hendricks had died in office in November 1885. Democrats turned his red bandana handkerchief into an emblem of the campaign, tying red bandanas to the top of canes in political parades, and manufacturing bandanas with the candidates' faces on them. Thurman's appeal came from his popularity among old-line Democrats, distrustful of Grover Cleveland's liberalism, and his known hostility to railroad monopolists. All the same, Thurman, who had retired from active politics, could not put on an active campaign, and added little to the ticket's chances.