A law executed to explain the actual meaning and intent of a previously enacted statute.
Courts have stated that Congress has the power to declare the proper construction of a statute by subsequent legislation. Courts are generally bound to apply subsequent legislative construction in lawsuits involving transactions that occurred after the enactment of the legislation. Provisions of expository statutes may be litigated due to the potential for a retroactive effect. For example, in Personal Finance Co. of Braddock v. United States, 86 F. Supp. 779 (D. Dela. 1949), Congress had enacted an expository statute clarifying a definition in a tax statute. The plaintiff sought a refund under the statute, claiming that it would have recovered the refund based upon judicial interpretations of the original statute. The U.S. District Court for the District of Delaware held that the statute, as amended by the expository legislation, could not be interpreted to have a retroactive effect because the plaintiff's right vested prior to the enactment of the expository act.