Courts as corruptions of government

Courts as corruptions of government

In other words, the court was interpreting the US Constitution, one of the sources of law in the US.

As I said before, people may reasonably disagree that this was a correct interpretation of that law and was instead new law, but the point is that if so, that's a failure of the system, not an application of it. Common law doesn't allow judges to make new law from whole cloth. At no point in the detailed written decision in Roe v Wade does the court say, "We think abortion is fine, so we nullify any law that says otherwise."

The U.S. Congress does not have the power to modify the U.S. Constitution all by itself, but it could certainly initiate an amendment and if 3/4 of the states agreed that abortion is not fine, the Supreme Court would be overruled and would start upholding criminal convictions for having abortions.

One way to have a system where the courts have less power is not to have a constitution - the legislative branch's power is unlimited. Another is to have a constitution that can be amended by a quick majority vote of the people, which many US states have. But that's not a common law vs civil law issue.