High Quality Content by WIKIPEDIA articles! The United States Tax Court is a federal trial court of record established by Congress under Article I of the U.S. Constitution, section 8 of which provides (in part) that the Congress has the power to "constitute Tribunals inferior to the supreme Court". The Tax Court specializes in adjudicating disputes over federal income tax, generally prior to the time at which the formal tax assessments are made by the Internal Revenue Service.