He was a persistent critic of successive party leaders, including Vladimir Lenin and Joseph Stalin, for which he spent years in prison and exile before being executed.
In November, he was transferred to Petrograd, then still the capital of Russia, to join Bukharin and Osinsky on the executive of the Supreme Council of National Economy, which was originally dominated by the left.
On 20 March 1919, he gave a speech to the Congress on the use of former Tsarist officers (termed "Specialists" within the party) and of political commissars in the Red Army.
Responding to accusations from Grigory Sokolnikov that he opposed the use of officers, which by this point had become a key part of Bolshevik military strategy, he denied favouring the use of partisan militias in the Russian Civil War.
But in April 1919 the Central Committee of the RKP appointed Smirnov as the first organiser for ChON volunteers to support the Red Army in the civil-war effort.
[8] During 1920, Smirnov, Osinsky, and Timofei Sapronov formed the Democratic Centralists, or 'Decists', a left wing opposition group that opposed the managerial system in industry, and advocated more democracy within the communist party.
In 1926, he and Sapronov formed the "Group of 15", which joined the United Opposition headed by Trotsky, Grigory Zinoviev and Lev Kamenev.
[9] On 29 January 1930, he was arrested for being five minutes late in reporting to the local Ogpu for a routine check, and sentenced to three years in prison, and held in an 'isolator' at Verkhne-Uralsk.
In early 1937, while serving in the Suzdal special prison, Smirnov sent letters to the People's Commissar of Internal Affairs Nikolai Yezhov and the USSR Prosecutor Andrei Vyshinsky, protesting against his detention.
On April 20 the same year, he was transferred to Moscow and, on 26 May 1937, the Military Collegium of the Supreme Court USSR under the chairmanship of V. Ulrich sentenced him to death for participating in a counterrevolutionary terrorist organization.
[14] Drafted in 1942, as a private in the Red Army he took part in the defence of Moscow, the reconquest of Belarus, and the capture of Konigsberg (Kaliningrad).