In 1911 he was appointed by President Taft as a special envoy to the German Emperor to present a statue of Baron von Steuben as a gift from Congress and the American people.

[2] He served as chairman of the Republican State convention at St. Joseph, Missouri, in 1896.

Bartholdt was elected president of the Interparliamentary Union at the conference held in St. Louis in 1904, wherein the following year he proposed "the most interesting recent suggestion for federating nations into a League of Peace".

[citation needed] Bartholdt was an Esperantist, and in 1914 he proposed a resolution to have Esperanto taught in American schools.

[4] During World War I, he was president of the American Independence Union, which campaigned for an embargo on munitions sales by United States companies to belligerent countries.