Final answer:
Boris Yeltsin announced political control over Russia after thwarting a coup attempt against Mikhail Gorbachev, which eventually led to the dissolution of the Soviet Union and the emergence of the Russian Federation.
Step-by-step explanation:
After the failed coup against Mikhail Gorbachev, Boris Yeltsin announced that his government had political control of the Soviet republic of Russia. Russia was the largest and most influential of the Soviet states, and Yeltsin's defiance against the coup played a significant role in its failure. Gorbachev's return to power was largely due to Yeltsin's efforts, which also included calls for the dissolution of the Soviet Union. Consequently, on December 25, 1991, the Soviet Union was replaced by the Commonwealth of Independent States, and Boris Yeltsin emerged as the leader of the Russian Federation, the most dominant state of the former Soviet Union.