Final answer:
Joseph Stalin's rise to power after Lenin's death allowed the official ideology of communism to be promoted in the USSR. This marked a leadership crisis in the country.
Step-by-step explanation:
After Lenin's death in 1924, Joseph Stalin rose to power and took control of the Soviet Union. Stalin advanced the official ideology of the totalitarian nation, which was focused on creating and promoting communism. He demanded strict conformity to Marxist ideology and conducted state-mobilized efforts to build Russian industry. Stalin's rise to power marked a leadership crisis in the USSR.