Asserted liberty rights not enumerated in the U.S. Constitution are generally considered under the substantive due process doctrine. Courts look only at narrowly defined interests and their history and traditions, and recognize only fundamental rights. This approach, however, fails to acknowledge the existence of nonfundamental rights that deserve recognition and a level of protection from improper legislation. As a supplement to its incomplete substantive clue process jurisprudence, the Supreme Court should examine the Ninth Amendment's history and traditions. Looking to this history and tradition will provide better guideposts for what types of rights should be protected. Employing the Ninth Amendment in this way will also help alleviate three primary reasons for the Amendment's disuse: the Ninth Amendment was not meant to apply against states, judges have no power to protect unenumerated rights, and the Ninth Amendment was only relevant under the now-disfavored penumbras and emanations test.
Joseph F. Kadlec, Employing the Ninth Amendment to Supplement Substantive Due Process: Recognizing the History of the Ninth Amendment and the Existense of Nonfundamental Unenumerated Rights, 48 B.C.L. Rev. 387 (2007), https://lawdigitalcommons.bc.edu/bclr/vol48/iss2/3