On this day in history, James Madison wrote a very long letter to Thomas Jefferson, then in France, making “some observations” about the deliberations on the constitution for Jefferson’s edification.
Madison began by noting that “It appeared to be the sincere and unanimous wish of the Convention to cherish and preserve the Union of the States.” He then explained there was general agreement that a mere confederation would be inadequate:
Hence was embraced the alternative of a Government which instead of operating, on the States, should operate without their intervention on the individuals composing them; and hence the change in the principle and proportion of representation.”
This extraordinary letter then went on to provide justification through examples of historical confederacies that failed, such as that of the Amphyctions, the Achaean League, the Helvetic System, and so on. Moreover:
A constitutional negative on the laws of the States seems equally necessary to secure individuals agst. encroachments on their rights. The mutability of the laws of the States is found to be a serious evil. The injustice of them has been so frequent and so flagrant as to alarm the most stedfast friends of Republicanism. I am persuaded I do not err in saying that the evils issuing from these sources contributed more to that uneasiness which produced the Convention, and prepared the public mind for a general reform, than those which accrued to our national character and interest from the inadequacy of the Confederation to its immediate objects.”
But, he argued, a balance was necessary:
The great desideratum in Government is, so to modify the sovereignty as that it may be sufficiently neutral between different parts of the Society to controul one part from invading the rights of another, and at the same time sufficiently controuled itself, from setting up an interest adverse to that of the entire Society. . . . In the extended Republic of the United States, The General Government would hold a pretty even balance between the parties of particular States, and be at the same time sufficiently restrained by its dependence on the community, from betraying its general interests.”
He ended by mentioning some of the compromises that were necessary to adjust for the different interests of different parts of the country. And of course, “S. Carolina & Georgia were inflexible on the point of the slaves.”
You can read the whole letter with its incredibly thorough description of the thinking that went into the construction of the Constitution here.