The breathtakingly broad language of the Ninth Amendment is both a blessing and a curse. It is a blessing for those seeking support for expansive theories of individual rights. Indeed, it is hard to conceive of a theory of individual liberty that cannot find at least rhetorical support in the Ninth Amendment's declaration of retained rights. It is not surprising, therefore, to find the Ninth Amendment invoked in support of everything from Dial-a-Porn to prostitution to organ selling. Once one decides that the Ninth Amendment refers to "other" unnamed individual liberties, there is literally no textual reason to exclude any unenumerated right. This, of course, is also the curse of the Ninth Amendment. The very fact that it seems to support even the most implausible claims makes courts reluctant to rely on the Ninth Amendment at all. In fact, the modern Supreme Court has studiously avoided the Ninth Amendment despite being prodded by parties before the court to rely on it.
This has not prevented scholars from developing a number of theories related to the Ninth Amendment. Most recently, Daniel Farber has invoked the Ninth Amendment in support of judicial reliance on international human rights. Randy Barnett has relied on the Amendment in support of a general "presumption of liberty," which places the burden on the government to justify intrusions on any individual activity that does not injure third parties. Although their individual rights theories of the Ninth Amendment differ in their details, both Farber and Barnett embrace a number of common assumptions about the Ninth Amendment: first, that the "other" rights of the Ninth Amendment are limited to individual rights; second, that the Ninth Amendment has nothing to do with the Tenth Amendment-in fact, the two clauses are generally interpreted in a manner placing them at odds with one another; third, like almost all scholars in the modern period, these individual rights theorists assume the Ninth Amendment was forgotten soon after its enactment, thus obviating the need to deal with any of its counter-interpretations or uses.
These assumptions are not unique to Farber and Barnett. They are repeated in one form or another in almost all modern Ninth Amendment scholarship. Recently, however, a great deal of historical evidence has come to light that calls into question all three of these myths about the Ninth Amendment. In this short essay, I will briefly discuss the critical aspects of this evidence in the hope that readers will be encouraged to explore a growing corpus of original sources that challenge many of the modern scholarly assumptions about this mysterious Amendment. I present a more in-depth look at the history and theory of the Ninth Amendment in recent volumes of the Stanford Law Review and the Iowa Law Review."
Kurt T. Lash, Three Myths of the Ninth Amendment, 56 Drake L. Rev., 101 (2008).