a Russian political party advocating a radical change in Russian government toward a constitutional monarchy like Great Britain's. It was founded in October 1905 by the Union of Liberation and other liberals associated with the zemstvos, local councils that often were centres of liberal opinion and agitation.

The Kadets dominated the first Duma in 1906, but the tradition of despotic rule, the dislocations caused by World War I (1914–18), and the growth of revolutionary fervour and agitation during the war caused other groups to claim the nation's attention. Succeeding Dumas saw a weakening of Kadet strength. Four of the members of the Provisional Government's first cabinet were Kadets, but the Bolsheviks (Bolshevik), seizing power, declared the Kadet organization illegal late in 1917, and the party's activities ceased within Russia.