1. Any copyright, patent, or other exclusive right granted to promote the progress of science and the useful arts, shall be limited in duration to a fixed number of years, determined at the beginning of such term.
2. Congress shall have no power to extend the term of any copyright, patent, or other exclusive right granted to promote the progress of science and the useful arts, or to retroactively grant such exclusive right to any work already in the public domain.
3. If any copyright, patent, or other exclusive right granted to promote the progress of science and the useful arts is already in existence and not expired at the time of the adoption of this amendment, and its term would have expired earlier under the law in effect at the time of the grant of such exclusive right, said term shall expire on a date determined by the law in effect at the time of the grant of such exclusive right. Provided, that this section shall not, for a period of five years following the ratification of this amendment, cause any exclusive right to expire that would not have expired were it not for the provisions of this section.
4. Congress shall have the power to enforce the provisions of this amendment by appropriate legislation.