Unconstitutional constitutional amendment

An unconstitutional constitutional amendment is a concept in judicial review based on the idea that even a properly passed and properly ratified constitutional amendment, specifically one that is not explicitly prohibited by a constitution's text, can nevertheless be unconstitutional on substantive (as opposed to procedural) grounds—such as due to this amendment conflicting with some constitutional or even extra-constitutional norm, value, and/or principle. As Israeli legal academic Yaniv Roznai's 2017 book Unconstitutional Constitutional Amendments: The Limits of Amendment Powers demonstrates, the unconstitutional constitutional amendment doctrine has been adopted by various courts and legal scholars in various countries throughout history. While this doctrine has generally applied specifically to constitutional amendments, there have been moves and proposals to also apply this doctrine to original parts of a constitution.