Question

The constitutional issue at the heart of United States v. Nixon is best described as

Answer 1

the answer is C. the extent to which the separation of powers was allowed.

Answer 2

I believe the answer is: whether the Supreme Court could hear the case.

At that time, President Nixon wanted to use his Executive previlege to avoid the supreme court from hearing his case and argued that it's all for the sake of national security. The court ruled against nixon and ordered him to hand over the tape which lead to his impeachment during the watergate scandal.