The Cold War enabled the Soviet Union to achieve great power status. In turn, this allowed the USSR to further its most important geopolitical goal: securing its vast borders. To this end, the Soviets were particularly active in the anti-colonial struggle, assisting armed guerrillas and resistance movements in their conflicts with colonial powers and their proxies. Through the anti-colonial movement, the Soviet Union was able to extend its worldwide influence while at the same time making its own borders more secure. The more allies could be secured internationally, the safer the USSR would be.
Yet in the long run, the Cold War destroyed the Soviet Union. As its sphere of influence grew, the Soviet Union found itself vulnerable to overreach, and this severely hampered its ideological struggle with the West. Quite simply, the USSR lacked the requisite economic strength to keep up with the West, and the United States in particular. As military spending escalated in the US, the Soviets had no choice but to follow suit. But with a much weaker economy than the Americans, the Soviets couldn't devote as many resources to the arms race as the United States. And whatever could be spent placed a crippling burden on an already creaking economy that was chronically inefficient and riddled with corruption.
Domestic living standards plummeted as the Soviet Union forlornly tried to compete with the United States, adding to the chronic shortages that were a major feature of the centralized command economy. What had proved quite an effective system during World War II was unable to deliver success in the Cold War. Once the nuclear arms race began in earnest, the writing was on the wall for the Soviet Union.