What proposal called for proportional representation in both houses of a bicameral Congress?

The Virginia Plan proposed a system of proportional representation in both houses of a bicameral Congress. This plan, articulated by delegates such as James Madison, was presented at the Constitutional Convention of 1787. It aimed to create a more robust federal government with a legislature that represented the states based on their population sizes. This meant that states with larger populations would have more representatives, thereby giving them greater influence in the legislative process.

The emphasis on population-based representation was a significant departure from the existing system under the Articles of Confederation, where each state had equal representation regardless of size. Ultimately, the Virginia Plan set the stage for debates about representation that led to compromises, such as the Great Compromise, which established the current structure of Congress with the House of Representatives having proportional representation and the Senate having equal representation for each state. This historical context illustrates the importance of the Virginia Plan in shaping the legislative framework of the United States.