Which of the following did NOT contribute to the fall of the Soviet Union
A) Soviet spending in Afghanistan
B) Soviet spending after the Cuban missile crisis
C) Soviet spending in Vietnam
D) Soviet spending in the 1980s

I believe C

Explanation:

This is because  the Soviet Union and communist Vietnam actually won Vietnam war and this greatly influenced relations between the Soviet Union and communist Vietnam.

the main reason that the constitution did not proclaim all men to be free and equal is because of the issue of slavery.