Why did the Provisional Government fail?
One of the main reasons that Russia's provisional government failed and why the Bolsheviks were able to gain power is the First World War. The war was a disaster for Russia- people were already very discontent at the failure of the war and the shortages it caused- it was a major cause of the March revolution to overthrow the Tsar. The war was already going badly when the June-July Russian offensive was a complete disaster. This was a huge blemish on the provisional government and for the first time the Bolshevik policy of ending the war became popular. There was mass-desertion in the army and discontent among the workers and peasants putting the provisional government in a very weak position. The party most interested in a quick overthrow of the provisional government (due to Lenin, see below), the Bolsheviks, especially benefited from this as by this time the other radical parties had joined the provisional government.
This allowed a very strong radical party to take advantage of the Provisional government's dire situation.
Another reason for the provisional government's failure is its weakness and its mistakes. The war and discontent following the conditions that forced the Tsar to abdicate still remained when the provisional government was formed. As stated above, a major cause of discontent was the war- there was opposition to military service and people were angry at how the war was going badly. The war also caused food shortages and very high prices, causing further discontent. It was clear Russia needed a strong government with the trust of the people to fix its predicament- the provisional government was not it- they were not elected by the people (merely the Duma) and so were not particularly popular. The formation of the Petrograd Soviet (and...