Oldenburg joined the liberal Constitutional Democratic Party (Kadets) in 1905; he served as a member of the State Council of Imperial Russia from 1912 to 1917. Following the February Revolution of 1917 he served in the Russian Provisional Government as Minister of Education. He set up the Commission for the Study of the Tribal Composition of the Population of the Borderlands of Russia at this time. Unlike his Kadet colleagues, he stayed in Russia after the October Revolution brought the Bolsheviks to power. Based on his acquaintance with Vladimir Lenin, he was able to develop an alliance between the Bolsheviks and Russian ethnographers, the former being more interested in nationalism amongst European peoples of the former Russian Empire, the ethnographers focusing more on the national question amongst its Asian peoples.