They do, but not proactively. You have to bring a case before the court for the precedent to get considered. Lots of things that are legal/illegal are only so

They do, but not proactively. You have to bring a case before the court for the precedent to get considered. Lots of things that are legal/illegal are only so because they haven't been tested in court. Precedents are also specific and sometimes the details of a case make it different enough that the precedent does not apply.