When Russia became a part of World War I, they had a lack of industrialization, which meant they had a significant disadvantage in the war. Compared to other nations who utilized modern weaponry and technology for the time, Russia had a considerably inferior military. This led to the war effort being extremely costly, resulting in many casualties and a significant downturn in the economy.
This poor economy led industrial workers to near starvation, making them believe that the government was incompetent. Thus, the Russian Revolution began.