In the modern legal systems there are a variety of sources of law. Judicial precedent is one of the legal sources; thus, precedents of Supreme Court, like enactments of parliament, are enforceable in courts. Them similarity between precedents and acts impose many problems such as rules, different, relationship of them and role of Supreme Court in interpretation of laws. But the most important problem is the possibility of changing previous precedent by posterior one. In our legal system the legislator has provided Supreme Court from such changes. Whereas, such act seemed to be conflicting with legal principles and constitutional law. Supreme Court cannot change enactments but it can change its precedents.
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