Question

What caused relations to deteriorate between the United States and the Soviet Union in 1979?
The United States invaded Afghanistan.
The Soviet Union invaded Afghanistan.
The Soviet Union hosted the Olympic Games.
The United States ratified the SALT II Treaty.

Answer 1

The Soviet Union invaded Afghanistan. This December 1979 invasion prompted U.S. condemnation, led to the U.S. boycott of the 1980 Moscow Olympics and other measures, and seriously worsened relations.