On the outbreak of the First World War Bubnov became involved in the anti-war movement in Kharkiv, whence he had been deported after being expelled from St Petersburg.

On 23 October, two weeks before the revolution, the Central Committee appointed a seven-man political council consisting of Lenin, Zinoviev, Kamenev, Trotsky, Stalin, Sokolnikov and Bubnov.

After the successful execution of the October Revolution, he was appointed Commissar for Railways, before being sent to Rostov-on-Don to organise resistance to the newly formed White Army of General Kaledin.

[10] In February 1918, he joined the Left Communists, and moved to Ukraine, to organise partisan detachments in the 'neutral zone' east of the German front line.

[3] He and Georgy Pyatakov, who led the left in the Ukrainian party, argued that Ukraine was not a signatory to the Brest-Litovsk Treaty, and that they were therefore entitled to organise partisan war against the Germans.

[11] In October 1918, Bubnov moved to Kyiv, which was ruled by Hetman Skoropadskiy, with German backing, and later by the Ukrainian nationalist Symon Petliura.

In 1922, he was appointed head of the Agitprop department of the Central Committee,[6] which meant he was working alongside Stalin, the new General Secretary.

The Declaration was organised and penned by future members of the Left Opposition, who supported Trotsky in the power struggle that followed Lenin's death.

In January 1924, while Lenin was incapacitated by a stroke, the head of the Political Directorate, Vladimir Antonov-Ovseenko and ardent Trotsky, supporter was sacked.

[4] Early in 1926, Bubnov was appointed head of a Soviet delegation to China, to investigate what seemed to be a breakdown in relations with the Chinese military authorities.

He then worked with Grigori Voitinsky and Fedor Raskolnikov on the "Preliminary Theses on the Situation in China", which was presented to the ECCI in November and December of that year.

[14] In October 1937, during the Great Purge, Bubnov arrived at the Kremlin for a meeting of the Central Committee, but was barred by the guards from entering.

[4] He was then still a member of the Central Committee, which convened on 4 December, and received a message from Stalin saying that Bubnov had confessed to being 'an enemy of the people' and a German spy.