Why did Russia leave World War I and how did its withdrawal change the war?

Russia left the First World War because military losses and economic hardship helped undermine governments that wanted to keep fighting. After taking power, the Bolsheviks made ending the war a priority. Withdrawal gave Germany a major military opportunity in 1918, but it did not guarantee German victory.

Follow three stages, rather than treating the 'Russian Revolution' as a single event that immediately ended the war:

The causes within Russia reinforced one another. Casualties and disrupted supplies weakened soldiers' willingness to fight. Wartime demands on transport and production made shortages and rising prices worse in cities. Continuing the war damaged the Provisional Government because it could not quickly deliver the peace or better living conditions people expected. The Bolsheviks could therefore present withdrawal as both a response to war weariness and a way to protect their new regime. Germany's renewed advance in February 1918 showed the danger of negotiating without an effective fighting force.

Do not describe the Provisional Government as simply a 'Menshevik government'. Its membership and coalition arrangements changed. Nor did the killing of Nicholas II and his family cause withdrawal: their deaths in July 1918 came after the treaty. Francis's telegram of 18 March 1917 records assurances that the new government would continue fighting.

The military consequence was that Germany could move troops from the east to the Western Front. Those reinforcements helped make the spring offensives possible before American forces reached their full strength. Yet Germany still faced supply problems, battle losses and the difficulty of turning advances into a decisive victory. Allied resistance, coordination and growing American participation also mattered.

Withdrawal gave Germany new opportunities; it did not decide the result. Germany lost in November 1918, but we cannot observe how quickly the Allies would have won had Russia remained in the war. The Brest-Litovsk diplomatic record provides evidence for the actual settlement, not for that 'what if' claim.

Try the Russian-withdrawal exercise in the First World War questions. Build your explanation in two parts: why Russia left, and how that changed the choices facing the armies still fighting in 1918.