The All Russian Constituent Assembly (Всероссийское Учредительное собрание, Vserossiyskoye Uchreditelnoye sobraniye) was a constitutional body convened in Russia after the October Revolution of 1917. It met for 13 hours, from 4 p.m. to 5 a.m., 18–19 January 1918, whereupon it was dissolved by the All-Russian Central Executive Committee, making the Third All-Russian Congress of Soviets the new governing body of Russia.
A democratically elected Constituent Assembly to create a Russian constitution was one of the main demands of all Russian revolutionary parties prior to the Russian Revolution of 1905. In 1906, the Tsar decided to grant basic civil liberties and hold elections for a newly created legislative body, the State Duma. However, the Duma was never authorized to write a new constitution, much less abolish the monarchy. Moreover, the Duma's powers were falling into the hands of the Constitutional Democrats and not the Marxist Socialists. The government dissolved the Duma, as was their legal agreement, in July 1906 and, after a new election, in June 1907. The final election law written by the government after the second dissolution on 16 June 1907 favored the landed and ruling classes. What little the Duma could do after 1907 was often vetoed by the Tsar or the appointed upper house of the Russian parliament. The Duma was therefore widely seen as unrepresentative of the lower working classes, and the demands for a Constituent Assembly that would be elected on the basis of universal suffrage continued unabated.
The Provisional Government was so named because it was made up of parliamentary figures, last elected (as the Fourth Duma) in 1912, who claimed provisional authority for managing the revolutionary situation in the midst of the First World War until a more permanent form of government could be established by an elected Constituent Assembly.
Grand Duke Michael had refused to ascend to his older brother Nicholas II's throne without the consent of an elected Constituent Assembly, and it was broadly assumed that an elected Constituent Assembly was the only body with the authority to change Russia's form of government. The Provisional Government claimed that it would organize elections once the First World War had concluded, but in spite of the initial agreement in July 1917, they declared Russia a republic and began preparations for elections in the "Preparliament", later named the Council of the Russian Republic. These actions triggered criticism from both left and right. Monarchists saw the declaration of a republican form of government in Russia as unacceptable, while the left considered the declaration a power grab intended to weaken the influence of the Soviets.