[3] He supported the Bolshevik Revolution and travelled with Walther Bringolf to Russia to represent the left wing of the Social Democratic Party of Switzerland.

[3] Humbert-Droz became after 1920 an outstanding leader in the international communist movement and travelled all around the world to organize the national sections of the Comitern.

After the 6th World Congress of the Communist International, Bukharin was politically isolated and only few people in the Moscow Apparatus stayed loyal to him, including Humbert-Droz,[8] who was disgraced along with his ally.

Humbert-Droz writes that he replied to Bukharin by criticising any rapprochement with Zinoviev and Kamenev and argued that resorting to individual terror would destroy the Bolshevik leadership.

[9]Boukharine me dit aussi qu'ils avaient decide d'utiliser la terreur individuelle pour se debarrasser de Staline.

[10] [Bukharin also told me that they had decided to use individual terror in order to rid themselves of Stalin].He managed to re-enter the Executive Committee of the Communist International after self-criticizing and capitulating.