The Russo-Japanese War accelerated the rise of political movements among all classes and the major nationalities, including propertied Russians. By early 1904, Russian liberals active in zemstvos, assemblies of nobles, and the professions had formed an organization called the Union of Liberation. In the same year, they joined with Finns, Poles, Georgians, Armenians, and with Russian members of the Socialist Revolutionary Party to form an antiautocratic alliance. They later promoted the broad, professional Union of Unions. In early 1905, Father Georgii Gapon, a Russian Orthodox priest who headed a police-sponsored workers' association, led a huge, peaceful march in St. Petersburg to present a petition to the tsar. Nervous troops responded with gunfire, killing several hundred people, and thus the Revolution of 1905 began. Called "Bloody Sunday," this event, along with the failures incurred in the war with Japan, prompted opposition groups to instigate more strikes, agrarian disorders, army mutinies, and terrorist acts and to form a workers' council, or soviet, in St. Petersburg. Armed uprisings occurred in Moscow, the Urals, Latvia, and parts of Poland. Activists from the zemstvos and the Union of Unions formed the Constitutional Democratic Party, whose members were known as Kadets.

Some upper-class and propertied activists were fearful of these disorders and were willing to compromise. In late 1905, Nicholas, under pressure from Witte, issued the so-called October Manifesto, giving Russia a constitution and proclaiming basic civil liberties for all citizens. The constitution envisioned a ministerial government responsible to the tsar, not to the proposed national Duma--a state assembly to be elected on a broad, but not wholly equitable, franchise. Those who accepted this arrangement formed a center-right political party, the Octobrists. The Kadets held out for a ministerial government and equal, universal suffrage. Because of their political principles and continued armed uprisings, Russia's leftist parties were in a quandary over whether or not to participate in the Duma elections. At the same time, rightists, who had been perpetrating anti-Jewish pogroms, actively opposed the reforms. Several monarchist and protofascist groups wishing to subvert the new order also arose. Nevertheless, the regime continued to function, eventually restoring order in the cities, the countryside, and the army. In the process, several thousand officials were murdered by terrorists, and an equal number of terrorists were executed by the government. Because the government was successful in restoring order and in securing a loan from France before the Duma met, Nicholas was in a strong position and therefore able to dismiss Witte, who had been serving as Russia's chief minister.

The First Duma, which was elected in 1906, was dominated by the Kadets and their allies, with the mainly nonparty radical leftists slightly weaker than the Octobrists and the nonparty centerrightists combined. The Kadets and the government were deadlocked over the adoption of a constitution and peasant reform, leading to the dissolution of the Duma and the scheduling of new elections. In spite of an upsurge of leftist terror, radical leftist parties participated in the election and, together with the nonparty left, gained a plurality of seats, followed by a loose coalition of Kadets and of Poles and other nationalities in the political center. The impasse continued, however, when the Second Duma met in 1907.