Professor John Zumbrunnen, University of Wisconsin-Madison
The 9th Amendment guards against any claim that the writing down of some rights (as in the Bill of Rights) should be taken as exhaustive. It makes explicit the idea that the people retain some rights that may not be written down. In Federalist 84, Hamilton highlights the potential dangers posed by a written bill of rights.
From Federalist 84
It has been several times truly remarked that bills of rights are, in their origin, stipulations between kings and their subjects, abridgements of prerogative in favor of privilege, reservations of rights not surrendered to the prince. Such was MAGNA CHARTA, obtained by the barons, sword in hand, from King John. Such were the subsequent confirmations of that charter by subsequent princes. Such was the Petition of the Right assented to by Charles the First in the beginning of his reign. Such, also, was the Declaration of Right presented by the Lords and Commons to the Prince of Orange in 1688, and afterwards thrown into the form of an act of Parliament called the Bill of Rights. It is evident, therefore, that, according to their primitive signification, they have no application to constitutions, professedly founded upon the power of the people and executed by their immediate representatives and servants. Here, in strictness, the people surrender nothing; and as they retain everything they have no need of particular reservations. “WE, THE PEOPLE of the United States, to secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America.” Here is a better recognition of popular rights than volumes of those aphorisms which make the principal figure in several of our State bills of rights and which would sound much better in a treatise of ethics than in a constitution of government.
But a minute detail of particular rights is certainly far less applicable to a Constitution like that under consideration, which is merely intended to regulate the general political interests of the nation, than to a constitution which has the regulation of every species of personal and private concerns. If, therefore, the loud clamors against the plan of the convention, on this score, are well founded, no epithets of reprobation will be too strong for the constitution of this State. But the truth is that both of them contain all which, in relation to their objects, is reasonably to be desired.
I go further and affirm that bills of rights, in the sense and to the extent in which they are contended for, are not only unnecessary in the proposed Constitution but would even be dangerous. They would contain various exceptions to powers not granted; and, on this very account, would afford a colorable pretext to claim more than were granted. For why declare that things shall not be done which there is no power to do? Why, for instance, should it be said that the liberty of the press shall not be restrained, when no power is given by which restrictions may be imposed? I will not contend that such a provision would confer a regulating power; but it is evident that it would furnish, to men disposed to usurp, a plausible pretense for claiming that power. They might urge with a semblance of reason that the Constitution ought not to be charged with the absurdity of providing against the abuse of an authority which was not given, and that the provision against restraining the liberty of the press afforded a clear implication that a power to prescribe proper regulations concerning it was intended to be vested in the national government. This may serve as a specimen of the numerous handles which would be given to the doctrine of constructive powers, by the indulgence of an injudicious zeal for bills of rights.