The Senate of the United States shall be composed of two Senators from each State. [U.S. Constitution, Article I, section 3, clause 1]
During the summer of 1787, the delegates to the Constitutional Convention in Philadelphia established equal representation in the Senate and proportional representation in the House of Representatives. Called the Great Compromise or the Connecticut Compromise, this unique plan for congressional representation resolved the most controversial aspect of the drafting of the Constitution.
The Virginia Plan, drafted by James Madison and introduced to the Convention by Edmund Randolph on May 29, 1787, proposed the creation of a bicameral national legislature, or a legislature consisting of two houses, in which the rights of suffrage in both houses would be proportional to the size of the state. When delegates from small states objected to this idea, delegates from the larger states argued that their states contributed more of the nations financial and defensive resources than small states and therefore ought to have a greater say in the central government. This proposal also reflected a vision of national government that differed from the government under the Articles of Confederation in which each state had an equal voice. Madison argued that whatever reason might have existed for the equality . . . when the Union was a federal one among sovereign States, it must cease when a national Government should be put into place.
Delegates from the smaller states insisted on preserving the equal vote they had enjoyed under the Articles of Confederation. A confederacy, New Jerseys William Paterson stated, supposes sovereignty in the members composing it & sovereignty supposes equality.
On June 11 the delegates voted to adopt proportional representation in the House of Representatives based on the whole number of white & other free Citizens, and three fifths of all other persons, meaning enslaved African Americans. Connecticuts Roger Sherman, with support from Oliver Ellsworth, also from Connecticut, immediately moved that states have equal suffrage in the Senate. Sherman stated that Everything depended on this. The smaller States would never agree to the plan on any other principle than an equality of suffrage in the Senate. The motion was defeated by one vote.
In response, William Paterson proposed what became known as the New Jersey Plan, presenting it to the Convention on June 15. The centerpiece of Patersons plan was a unicameral (one-house) legislature in which each state had a single vote. The Convention voted down Patersons proposal on June 19 and affirmed its commitment to a bicameral legislature on June 21.
The small-state delegates continued to protest proportional representation in the Senate with increasingly heated language, threatening to unravel the proceedings. When another vote on equal representation in the Senate resulted in a tie on July 2, however, the small shift opened the possibility for compromise.
The Convention appointed a Grand Committee to reach a final resolution on the question. The committee reported the original Sherman compromise proposal with the added provision, suggested by Benjamin Franklin of Pennsylvania, that revenue and spending bills would only originate in the House. Madison and others continued to press their case for proportional representation in the Senate and to oppose a House monopoly on revenue bills, while some small-state delegates were reluctant even to support proportional representation in the House. On July 16, delegates narrowly adopted the mixed representation plan giving states equal votes in the Senate.