The Politburo is a small group of men who climbed the ranks of the party through an ordered path from local party soviets (nomenklatura) to leadership.
Tendency to value isolation in Russia comes from Tsar Peter the Great, who used the western model to modernize Russia with a stronger army, a navy, an infrastructure of roads and communication, a reorganized bureaucracy, and a “Window on the West.”
Gorbachev introduced Glasnost, more open discussion and criticism of the government by citizens, which turned into hostility and revolted because people wanted independence from Soviet control.
Gorbachev introduced Democratization, keeping the old Soviet structure and using some democracy, creating people's deputies with directly elected officials and a new position of president that was selected by congress.