The United States Tax Court is a federal trial court established by Congress under Article I of the U.S. Constitution, section 8. The Tax Court specializes in adjudicating disputes over federal income tax, generally prior to the time at which formal tax assessments are made by the Internal Revenue Service. The U.S. Tax Court is not an agency of, and is independent of, the executive branch. The U.S. Tax Court is the only forum in which taxpayers may file a case without having first paid the disputed tax in full. Tax Court judges are appointed for a term of 15 years, subject to presidential removal for actions related to neglect, inefficiency, or malfeasance.