What happened in Russia in 1917 that led the United States to justify its involvement in World War I as a fight for democracy? A.) Russia signed a military defense treaty with France and Great Britain. B.) Russia signed the Treaty of Brest-Litovsk and made peace with the Germans. C.) Russian revolutionaries overthrew the Czar and established a provisional government. D.) Russian Bolsheviks, under Vladimir Lenin's leadership, toppled the provisional government.