Tennesseans area about to elect a new senator, so we're going to review how it came to be that each state in our nation has the same number of senators serving in congress: two.
In 1787, delegates to the Constitutional Convention in Philadelphia established equal representation in the Senate and proportional representation in the House of Representatives. It was called the "Great Compromise" or the "Connecticut Compromise" and resolved the most controversial aspect of the drafting of the Constitution.
Some states with lower population bases had threatened to leave the Convention if both houses of congress were headed toward proportional representation. Some delagates sought compromise between large-state and small-state interests.
As early as 1776, Connecticut’s Roger Sherman had suggested that Congress represent the people as well as the states. During the 1787 convention, Sherman proposed that House representation be based on the population, while in the Senate, the states would be equally represented.
On July 16, delegates narrowly adopted the mixed representation plan giving states equal votes in the Senate within a federal system of government.
How many per state?
According to constitutional commentator Joseph Story (1779-1845), few, if any, delegates considered one senator per state sufficient representation. Lone senators might leave their state unrepresented in times of illness or absence and would have no colleague to consult with on state issues. Additional senators, moreover, would increase the size of the Senate, making it a more knowledgeable body and better able to counter the influence of the House. On the other hand, a very large Senate would soon lose its distinctive membership and purpose and actually decrease its ability to check the lower house or to allow senators to take personal responsibility for their actions.
Given these considerations, delegates had a limited choice regarding the number of senators and debated whether it should be two or three per state. Only Pennsylvania voted in favor of three senators. When the question turned to two, Maryland alone voted against the measure.
In its final form, the clause in the Constitution says simply, “The Senate shall be composed of two senators from each state."
Term of office
James Madison pushed for senators to serve six-year terms, saying it would have a stabilizing effect on the new national government. He also said long terms would control turnover in the legislature, allowing senators to take responsibility for measures over time and making senators largely independent of public opinion.
The reasoning behind the Senate’s class system
Framers hoped biennial elections would bring stability to the Senate, and in turn, to other branches of the new government. By gradually changing members, class rotations would prevent senators from permanently combining for “sinister purposes,” protect the Senate from a rapid turnover in ideas, and encourage senators to deliberate measures over time. Most important, as the federal government’s only continuing body, the Senate could provide leadership after major elections and during other periods of national uncertainty.
At the start of the first session of Congress in 1789, the senators were divided into the three classes by lot with same-state senators assigned to separate groups. The first class’ term expired in two years, the second in four years, and the third in six years. Subsequent elections to all classes were for the full six-year Senate term.
Source: The U.S. Senate