Final answer:
President Carter announced the boycott of OPEC oil on January 20, 1980.
Step-by-step explanation:
President Carter announced the boycott of OPEC oil on January 20, 1980. In response to the Soviet Union's 1979 invasion of Afghanistan, Carter declared that if the USSR did not withdraw its forces, the United States would boycott the 1980 Summer Olympic Games in Moscow. The Soviets did not retreat, and the United States did not send a team to Moscow. Only about half of the American public supported this decision, and very few countries joined the boycott.