How did World War One weaken Tsar Nicholas IIs government?
They were horribly woefully unprepared for the war, so it went very very badly. The Russian minister of defence for example was a proponent of the bayonet charge, so Russia had a very small amount of artillery and machine guns at the wars outset. Fighting a war and losing badly weakens most governments. Morale plummets in the army, desertion rates go up, and the war was fabulously expensive compared to all previous wars, so the government had problems on that front too. You might say that the war didn’t so much as weaken the government as put it in a position where it’s manifold faults became glaringly obvious. And the war wildly strengthened internal opposition to the Tsar, easy to recruit followers when a pointless war is being lost and the economy is tanking.
