The US and USSR engaged in proxy wars by

Some of those are very well-known and documented such as Vietnam, Afghanistan, and Angola, but there were also a few lesser-known conflicts in which Soviet and American troops indirectly slugged it out against one another. The Congo, Laos, and Ethiopia saw brutal warfare as these two superpowers fought for supremacy.The answer to this question is that they fought against one another in other conflicts, but never took the war to each other directly.

Explanation:

i dont know cuh

answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;