One of Soviet leader Mikhail Gorbachev's historic reforms was the ending of

Ending of one party politic

Was the ending of the cold war

He did this by introducing far reaching reforms in the government, such as glasnost and perestroika. He signed denuclearization treaty. Gorbachef however had saw the seed of freedom and the soviets wanted more, which led to the disintegration of the soviet, effectively ending the cold war. Gorbachef was ever willing to grant independence to many willing states of the union.