Russia left World War 1 before it ended because of the outbreak of the Russian Revolution in 1917. The revolution resulted in political unrest and ultimately the overthrow of the Tsarist regime, leading to the signing of the Treaty of Brest-Litovsk in March 1918, which officially ended Russia's involvement in the war. The new Bolshevik government under Vladimir Lenin prioritized consolidating power and implementing socialist reforms domestically, rather than continuing to fight in a costly and unpopular war.
