Containment wasn’t so much a strategy in itself as it was an overarching goal that various strategies supported. Several of these strategies were quite successful, such as the Korean War and the covert activities in Afghanistan. They shored up and emboldened weaker allies, forced the communists to expend financial and political capital, and generally made it clear the US-led West was willing to push back.

The “domino theory” used to justify US intervention in Vietnam was also a containment strategy. While the domino theory is historically tainted for its association with that divisive and seemingly failed war policy, a case can be made that US involvement in Vietnam did prevent communism from spreading further south or east in the region. The extent to which this is true is certainly debatable, but many have claimed that delaying Vietnam’s fall to the communists by a decade or more bought valuable time for neighboring nations to be strengthened against communism.

Regarding whether containment contributed to the collapse of the USSR, I would argue “not really“. The USSR collapsed largely due to its own internal economic and political failures. Yes, the 1980’s arms race (which the Soviets could not afford, literally) and their defeat in Afghanistan contributed to the Soviet dissolution. The ultimate Soviet implosion was, however, primarily due the fact that the failures of its own autocratic rigidity and absurdly inefficient economy had become impossible to ignore.

Mikhail Gorbachev in the 1980’s tried to reform the politically stale and economically moribund Soviet system by allowing more openness and transparency (glasnost) as well as economic and political restructuring (perestroika). This backfired. Rather than injecting new life into Soviet socialism, it showed Soviet citizens just how badly that system had failed them and, in turn, it enabled them for the first time to actually speak up about it. A critical mass of Soviet citizens rightfully decided the system was beyond saving, and so the various republics began breaking away. Everything else- Afghanistan, Poland, the arms race- helped to accelerate this collapse, but the real proximate cause was the Soviet system itself.