The collapse of the soviet union was caused by the prolonged stagnation of its economy in the 70s and 80s. This lead to all the events that followed (glasnost, perestroika, etc.) in failed attempt to fix it.

And the cause for the Era of Stagnation in the mid-1970s? The Cold War. Starting with the war in Afghanistan in 1979, funded of course by the US, this aggravated the stagnation and then led to a period of economic standstill between 1979 and 1985. (The USSRs economy was somewhere between 30% and 50% that of the US at the time). Couple with added global military pressure from the west caused the Soviets to put military buildup at the expense of domestic development. This kept the USSR's GDP at the same level during the first half of the 1980s. As spending out stripped both growth and capacity, again due to military spending, the rest as they say is history.

I don't see how that would have happened without the military pressure from the west. Look at China, it didn't have those costs, and it's still around, as is Cuba, Venezuela, etc. they didn't call it the Cold War for nothing, and it was expensive!