Final answer:
The rise of Mikhail Gorbachev, the implementation of glasnost policies, economic stagnation and political unrest, and the weakening of the Warsaw Pact all undermined the power and unity of the Soviet Union in the 1980s.
Step-by-step explanation:
In the 1980s, several developments undermined the power and unity of the Soviet Union. One of these developments was the rise of Mikhail Gorbachev, who implemented policies of perestroika (economic restructuring) and glasnost (political openness). These policies aimed to make the Soviet Union more economically and politically progressive, but they ultimately contributed to the unraveling of the Soviet system.
Additionally, the Soviet Union faced economic stagnation and political unrest, which further weakened its power and unity. Lastly, contrary to strengthening the Warsaw Pact, the Soviet Union's satellite states sought independence in the late 1980s, leading to the eventual dissolution of the Soviet Union in 1991.