Let me start by saying that I am not a "Constitutional Scholar" and I am not a lawyer. The information I am posting here is written in the simplest of terms and is certainly not all-encompassing. It is intended only to clarify a couple of points which are patently incorrect. First, that the Supreme Court makes laws. They do not. ONLY Congress can make laws. Secondly, that their decision is the final word on a particular issue. It is not.
First, how does a case get to the Supreme Court? The most important thing that has to happen is that someone is adversely affected by a particular law and files a lawsuit. It goes through the court system, and up the court system through the Appellate Courts until the only one left is the Supreme Court. IF the law which is being challenged includes some questions of Constitutionality, the lawyers may file a petition with the Supreme Court asking them to hear the case, and outlining the areas which they feel are unconstitutional (this is called a Writ of Certiorari, or Cert) If the Court accepts the Writ, the case will be heard. Again, the things which are important are: a) a law was passed b) the law infringed on someone's rights c) a lawsuit was filed challenging the law d) there are Constitutional questions to be addressed and/or legal issues undecided and e) the Court Agreed to hear the case.
When the Court decides a Constitutional case, they will make the most narrow decision possible and they address ONLY the issues which deal with questions of Constitutional rights. It is entirely possible that only very specific sections of laws will be challenged, and those are the sections the Court will decide. The Court cannot EVER arbitrarily enter an opinion on any law which has not been challenged in a lower court. For this reason, it it highly likely that there are thousands and thousands of "unconstitutional" laws on the books which will never be declared Unconstitutional because there has been no legal challenge to those laws.
So the Court has two options when they look at a case. Confirm that it is Constitutional, or strike it down. It is at THIS POINT that the misunderstanding seems to occur. If a law has been declared Unconstitutional, the Court's decision will tell us exactly why - in minutia. That is not "making law", it is telling Congress that the way they drafted the law is outside the guidelines of the Constitution. It is the "final word" ONLY in that the law in question was invalidated as written.
So, at this point, what can be done? Nothing? That's what most people seem to think. Well, it's not true. Once a law is struck down the ball is back in Congress's court. They have three choices. They may a) REWRITE the law in a manner which does not conflict with the Constitution, or b) Introduce an Amendment to the Constitution to meet their objectives or c) do Nothing.
The most recent case, of course, where many people are screaming about a "Bad Decision" by the Court is Citizens United. In fact, the decision itself was absolutely correct. The EFFECT of the decision is lots and lots of corporate money in the election process. Is that the fault of the Supreme Court? ABSOLUTELY NOT. It is the fault of Congress, who had every opportunity to re-write the law and chose NOT to. Of course they did it because it suited their own purposes - but never ever ever forget this important fact - IT WAS NOT THE SUPREME COURT'S FAULT THAT CONGRESS REFUSED TO ACT TO REVERSE THE IMPACT OF THIS DECISION. It is NOT the Supreme Court's place to look at the potential outcome of a ruling - in fact, it is unnecessary. Why? Because their decisions put the ball BACK IN CONGRESS'S COURT. So the next time you want to place blame for a Supreme Court ruling - think about this article and ask your Congressman WHY they aren't taking action to fix the problem.
P.S. If there are any Constitutional Scholars out there who wish to correct anything I may have said which was WRONG, please feel free to do so.
P.P.S. Setting a legal precedent in a "common law" case is NOT the same as writing legislation.