Answer:
The detail that provides the most cultural context for this excerpt about the Cold War is The Pentagon was worried that the shattered remains of the Soviet Union might be rebuilt before the United States.
Step-by-step explanation:
The two principal countries involved in the Cold War were the United States of America and the Soviet Union this represents a key factor in term of cultural context, this sets the time and the kind of life and social environment that the countries were living at, the countries were in a big battle and they both fought to win as the comparison in the paragraph with the two boxers.