Do judges have to follow precedent law or can they make a ruling against it?
Judges have to follow precedent — but this means that judges have to follow precedent when adjudging on the same or similar set of facts. In practice, the exact set of facts rarely re-occur, and judges can often pick which facts are judicially noticable as they wish in order to do justice. In addition, where a subjective element is part of the equation, this can often be found to result in a different ruling. In addition only rulings by higher courts to which a right of appeal lies can be binding. A ruling in a court which is not superior in the hierarchy can only be persuasive.