  The precise operation of stare decisis varies from one legal system to another. It is common for courts lower in a judicial hierarchy to be strictly bound by the decisions of higher courts, so that Federal Court judges in the United States are bound by decisions of the Federal Court of Appeals for their circuit, and the English Court of Appeal is bound by decisions of the House of Lords. The lower court is ‘strictly’ bound because it has no power to overrule the higher court's decision.  Equally, most appeal courts are bound by their own earlier decisions, though they are generally entitled in certain circumstances to overrule those decisions. There is enormous variation in the circumstances that are necessary for a court to overrule one of its own decisions: at a minimum it must regard the earlier decision as wrongly decided, but generally more is required than this, e.g. that the decision is ‘clearly’ or ‘plainly’  wrong.[3].  Finally, courts are generally not bound by the decisions of lower courts: the House of Lords for example is not bound to follow decisions of the Court of Appeal and is free to overrule such decisions if it takes a different view of how the case should have been decided.