Became a famous lawyer in Petersburg. One of the founders and, with Miliukov, practically the leader of the Cadet Party. Member of the Central Committee of the Cadets.
Member of the 1 st Duma, signed the Vyborg Manifesto. Opposed the October Revolution 1917. Minister of Foreign Affairs in the Crimean government in 1919.
Emigrated to France the same year. Lived in Paris. Throughout his life, in Russia and abroad, very active in various Jewish political, social and cultural organizations. His memoirs, Nedavnee, Paris, 1926, contain memorable portraits of pre-revolutionary Russian lawyers, judges and politicians.
One of the best known and most highly respected representatives of the Jewish community in Russia before the revolution.