When this nation was founded under the document that we call our Constitution, much debate surrounded the place of the central government in the lives of the people. The Anti-federalists (true federalists, mind you, that wanted a severely limited central government) had the notion that small was better, and that local government, i.e. State government, would be more responsive to the needs, wants and values of the people. They had intimate experience with a government "far away," and feared the potential of tyranny in such government.
Yet as much as the founders feared tyranny, they feared also a "too democratic government." Much was made of the potential for "mobocracy," and the resulting possibility of violent swings of temper within a necessarily factionalized electorate.
The states, some already having over 150 years experience in the minding of their own affairs, feared a loss of their own sovereignty should the new and national constitution be ratified. After all, who could possibly be a better arbiter of the people's wishes, and who could more completely recognize the needs of the people than the states themselves?
Thus the idea of a bicameral legislature was born. The Congress, representing the interests of the people or "mob", and the Senate, representing the interests of the state within the legislative framework. Two provisions of the Senate's body helped fully realize the State's interest: First, there would be equal representation of each state within the body by the election of two senators from each of the several states. Second, the Senators would be elected not by the people, but by the legislatures of the several states themselves.
As The Farmer remarked in The Philadelphia Independent Gazeteer, on 4/15/88:
…advocates of the new system, take as their strong ground the election of senators by the state legislatures, and the special representation of the states in the federal senate, to prove that internal sovereignty still remains with the States.
It must be remarked here that The Farmer did not believe the truth of this argument, but is stating that this argument was proffered by the Federalists that favored ratification of the constitution. The argument of the Senate as a protector of state sovereignty was, however accepted by many anti-federalists.
Robert Yates another Anti-Federalist writing under the pseudonym Brutus in Anti-Federalist # 63 remarks about Senators in the proposed constitution:
The Senators represent the states, as bodies politic, sovereign to certain purposes. The states being sovereign and independent, are all considered equal, each with the other in the senate. In this we are governed solely by the ideal equalities of sovereignties; the federal and state governments forming one whole, and the state governments an essential part, which ought always to be kept distinctly in view, and preserved. I feel more disposed, on reflection, to acquiesce in making them the basis of the senate, and thereby to make it the interest and duty of the senators to preserve distinct, and to perpetuate the respective, sovereignties they shall represent. . . .
Regardless of whether or not the Senate could or could not protect the sovereignty of the states within the federal framework, it is clear from just these two citations, that within the clockwork of the proposed Constitution, the Sovereignty of the States was thought by all a necessary adjunct to liberty.
The Vermont Farmer 2/07/10