Explicate the diplomatic doctrine the president followed, with reference to specific actions or events that occurred. Describe the effects of these diplomatic efforts for the U.S. and other countries
If I recall correctly, I believe the basic foreign policy doctrine of the Reagan administration was "peace through strength." The goal was to make the U. S. so strong that no other country would dare to attack or cause major problems. I recall that the Reagan administration was ridiculed for calling one kind of missile the "peacekeeper." I never quite understood way this term struck so many people as ridiculous, since we think of armed law-enforcement officers as keepers of the peace.
One of his major diplomatic doctrines was to put a lot of pressure on the Soviet Union. He was personally friendly with Mikhail Gorbachev, but he was very tough on the Soviets. This was the president who did not have any problem with referring to it as the "Evil Empire." You can argue that the effect of this was to help pressure the USSR until it fell apart and the Cold War ended.