What are two limits placed upon the powers of the United States Supreme Court.
First, the Supreme Court must wait for cases to try to come up from the lower courts. The Supreme Court, therefore, is not allowed to introduce their own cases. They must simply wait for cases to reach them as the case goes through the process of being tried and retried (through appeals).
Second, the Supreme Court only has the ability to make a ruling on cases which it presides over. What this results in is that the Supreme Court does not have the power to enforce any rulings made by the court itself. Instead, the power to enforce the ruling of the Supreme Court is left to the Legislative and Executive Branches.
One last limitation of the Supreme Court is the justices themselves. People have to remember that the justices are people. People can, and do make mistakes, have prejudices, and lapses in judgement. While Americans would like to think that they do not make mistakes, "to err is human."