He belonged to the Assembly of Russian Citizens (Vene Kodanikkude Kogu, Собрание русских граждан).
However, Sorokin, together with the three deputies representing the Baltic German minority, was not one of the signatories of the Estonian Declaration of Independence on 19 May 1919; he abstained.
He was a candidate for the center-right Russian National Federation in Estonia (Vene Rahvuslik Liit Eestis, Русский национальный союз в Эстонии), founded in 1920.
He remained, along with Nikolai Kurtšinski and Peeter Baranin, as a leading member of the Russian minority in Estonia in the interwar period.
However, he also failed to assemble the fragmented minority of large social differences into a party or association, as was the case with the Baltic Germans.