Impact on international relations
President Richard Nixon sought to reach a reduction of tension with the USSR in an attempt to divide the two communist superpowers in their support of North Vietnam. Both the USA and the USSR tried to distance themselves from China.
The Nixon Doctrine
Nixon announced that the USA would not make any more military commitments. Its allies would have to take care of their own security.
The Domino Theory (only partly confirmed)
Communism had spread to North Korea in 1948 and China in 1949. Laos and Cambodia had also become communist after 1975, but it did not spread into the rest of South East Asia as was feared.
Although Eastern Europe had become communist after the war, it had not spread to Western Europe. However, there were large communist parties in many European countries, so the threat was ever-present.
It was shown that communism may have spread to neighbouring countries but this outcome was not guaranteed.