Final answer:
The framers of the U.S. Constitution required a two-thirds majority in Congress and three-quarters of state legislature approval for amendments to ensure the Constitution could adapt to changes without being impeded by the requirement of unanimous consent, which proved impractical under the Articles of Confederation.
Step-by-step explanation:
The framers designed the Constitution to avoid the issues plaguing the Articles of Confederation, which required unanimous consent for amendments—practically an impossible condition. Recognizing the challenges of obtaining unanimous agreement, the framers sought a balance that allowed for adaptability without sacrificing the entire union's stability. They instituted a new amendment process that specifically required a two-thirds majority in both houses of Congress and the ratification by three-quarters of the state legislatures to approve a change. This ensured the Constitution could evolve with the nation but avoided the gridlock and inefficiency of the previous system.
This decision was partially influenced by concerns that numerous proposed amendments could halt Congressional action until all were addressed. The framers also believed it was unlikely that state legislatures would willingly cede power and opted for specially elected ratification conventions. They needed to secure the new nation's survival and success without the largest and most influential states' support, notably Virginia and New York. Thus, requiring all states to agree on amendments would have been counterproductive and possibly jeopardized the entire constitutional framework.