How did US foreign policy change after 1981?
1981 marked the beginning of the presidency of Ronald Reagan. Reagan, along with his Secretary of State George Schulz formed their own brand of American foreign policy. One characterized by "peace through strength” and an eventual end to the Cold War.
Specifically, the centerpiece of this new policy was the Reagan Doctrine. The Regan Doctrine was defined as a more aggressive stance on Soviet proxies around the world. The Soviet Union at the time was providing extensive political and financial support to many emerging nations in Africa, Asia and Latin America; these were known as proxy nations.
Prior to 1981 the U.S had a policy of containment concerning these nations. This meant that the U.S was content to allow these nations to continue their relationship with the USSR, so long as their socialist tendencies did not continue to spread.
However in 1981 with the rise of the Reagan Doctrine the U.S sought to roll back the Soviet influence in these nations, and replace them with America's own brand of capitalism and democracy. To achieve this Reagan allowed for increased operations, such as supporting regime change and occasionally more aggressive covert or overt military action.