The August 1991 coup attempt in the Soviet Union was organized by people who opposed Mikhail Gorbachev. Obviously, these people weren't satisfied with how the president ran things in the Soviet Union, due to his unsuccessful reforms and implementations, which is why they decided to rebel and start a coup against their "ruler." Although it wasn't successful (it ended after only two days), it was still an important reason why the Soviet Union was dissolved a couple of months after the coup.