Question

How did the Brezhev Doctorine and the domino theory affect the foreign policies of both the United States and the Soviet Union during the cold war?

Answer 1

@whpalmer4

Answer 2

Both were geopolitical in nature that followed essentially the same outcome -- that if one nation in an area were to be "infected", it would spread to neighboring nations and compromise the security of the region. For the Americans, they were afraid that if one nation in a region had turned communist, others around it would follow like a domino trail. That's what they were worried about in Vietnam/Southeast Asia.

For the Soviets, it was the same thing in Eastern Europe. They were concerned that if any one nation swayed too far towards liberalization and capitalism, it would spell an end to their control of the region.

So both essentially played a geopolitical game with nations. They tried to influence, directly or indirectly, potential allies around the world in order to keep the other side from getting to them first. Things like economic aid, military supplies for rebel movements, propaganda, etc.. were often used as tools towards this end. Again, one of the biggest results of this was the Vietnam War where American was drawn into supplying and defending democratic South Vietnam against Soviet-backed North Vietnam.