Twenty-seventh Amendment to the United States Constitution

The Twenty-seventh Amendment (Amendment XXVII, also known as the Congressional Pay Amendment or the Congressional Compensation Act of 1789) to the United States Constitution states that any law that increases or decreases the salary of members of Congress may take effect only after the next election of the House of Representatives has occurred. It is the most recently adopted amendment but was one of the first proposed.

Source: Wikipedia — Twenty-seventh Amendment to the United States Constitution (CC BY-SA 4.0)