8, what is the primary power of the courts?

I belive it is: The federal courts' most important power is that of judicial review, the authority to interpret the Constitution. When federal judges rule that laws or government actions violate the spirit of the Constitution, they profoundly shape public policy.

The most important power the court has is the power to interpret amendments and the Constitution. The federal courts can say that some laws are unfair, which will change the way the public sees/follows that law. This is called Judicial Review.