They are not limited to "interpreting"law. Once again, your abject ignorance of the constitution rears its ugly head. They are empowered to determine if any law passed violates a provision of the Constitution. If that laws does, the Supreme Court is obligated to strike it.
Izzatsew?
Enlighten us sploogy, with the article or amendment from the Constitution that so empowers the court?
Tell me, you drooling retard, have you heard of "Marbury V. Madison?" Do you have any idea what the relevance of the ruling was?
The Court and Constitutional Interpretation - Supreme Court of the United States
The Constitution of the United States is a carefully balanced document. It is designed to provide for a national government sufficiently strong and flexible to meet the needs of the republic, yet sufficiently limited and just to protect the guaranteed rights of citizens; it permits a balance between society's need for order and the individual's right to freedom. To assure these ends, the Framers of the Constitution created three independent and coequal branches of government. That this Constitution has provided continuous democratic government through the periodic stresses of more than two centuries illustrates the genius of the American system of government.
The complex role of the Supreme Court in this system derives from its authority to invalidate legislation or executive actions which, in the Court's considered judgment, conflict with the Constitution. This power of "judicial review" has given the Court a crucial responsibility in assuring individual rights, as well as in maintaining a "living Constitution" whose broad provisions are continually applied to complicated new situations.
While the function of judicial review is not explicitly provided in the Constitution, it had been anticipated before the adoption of that document. Prior to 1789, state courts had already overturned legislative acts which conflicted with state constitutions. Moreover, many of the Founding Fathers expected the Supreme Court to assume this role in regard to the Constitution; Alexander Hamilton and James Madison, for example, had underlined the importance of judicial review in the Federalist Papers, which urged adoption of the Constitution.
Hamilton had written that through the practice of judicial review the Court ensured that the will of the whole people, as expressed in their Constitution, would be supreme over the will of a legislature, whose statutes might express only the temporary will of part of the people. And Madison had written that constitutional interpretation must be left to the reasoned judgment of independent judges, rather than to the tumult and conflict of the political process. If every constitutional question were to be decided by public political bargaining, Madison argued, the Constitution would be reduced to a battleground of competing factions, political passion and partisan spirit.
Despite this background the Court's power of judicial review was not confirmed until 1803, when it was invoked by Chief Justice John Marshall in Marbury v. Madison. In this decision, the Chief Justice asserted that the Supreme Court's responsibility to overturn unconstitutional legislation was a necessary consequence of its sworn duty to uphold the Constitution. That oath could not be fulfilled any other way. "It is emphatically the province of the judicial department to say what the law is," he declared.
In retrospect, it is evident that constitutional interpretation and application were made necessary by the very nature of the Constitution. The Founding Fathers had wisely worded that document in rather general terms leaving it open to future elaboration to meet changing conditions. As Chief Justice Marshall noted in McCulloch v. Maryland, a constitution that attempted to detail every aspect of its own application "would partake of the prolixity of a legal code, and could scarcely be embraced by the human mind. . . . Its nature, therefore, requires that only its great outlines should be marked, its important objects designated, and the minor ingredients which compose those objects be deduced from the nature of the objects themselves."