chief Comintern agent in China in the 1920s, who built the loosely structured Nationalist Party (Kuomintang) of Sun Yat-sen into a highly centralized Leninist-style organization.

Borodin joined the Bolshevik party in Russia in 1903. In 1906 he was arrested and exiled. The same year he emigrated to the United States, attended Valparaiso University, Indiana, and later founded a school for émigrés in Chicago. After the Russian Revolution of 1917 he returned to Russia and was dispatched as a communist agent to Scandinavia, Mexico, Spain, Turkey, and Great Britain. He went to China in 1923 as an adviser to Sun Yat-sen, after the Nationalist leader acquiesced in the Soviet wish that Chinese communists be allowed to join the Kuomintang. Besides helping to restructure Kuomintang organization and ideology, Borodin gave the Chinese Nationalists Soviet aid in developing a party army, which made them a powerful force in Chinese politics. After Sun Yat-sen's death in 1925, Chiang Kai-shek, back from training in Moscow, became head of the army. In 1927 Chiang broke with the communists, and Borodin left the country.

Returning to Moscow, Borodin served as deputy people's commissar for labour, deputy director of Tass news agency, and, from 1932, editor of the Moscow Daily News, published in English. He disappeared in February 1949 in a wave of arrests directed by Joseph Stalin against Jewish intellectuals. He died in 1951 in a Siberian labour camp.