Article Three of the United States Constitution
There is one specific power that Clause 2 does not give the federal judiciary.  Clause 2 says that the federal judiciary has power over "the laws of the United States."  However, it does not say that the federal courts have power over the laws of individual states.  Also, when Congress passed the Judiciary Act of 1789, they also never gave the federal courts this power.  This means that the federal courts can only review or change the decisions of state supreme courts if the state decision may have broken a federal law or the Constitution.  The federal courts had no power to review or change state supreme court decisions that were just based on state laws.  Basically, this gave each state supreme court the final say over the laws in their state.  Different states could decide completely different things, so the laws might be completely different in one state than another.