How can an amendment to the Constitution be proposed?

An amendment to the Constitution can be proposed through two primary methods, both of which reflect the federal nature of the United States government and the need for a broad consensus. The first method is by a two-thirds majority vote in both the House of Representatives and the Senate, which ensures that a significant portion of the elected representatives supports the proposed change. The second method is through a convention called for by two-thirds of the state legislatures. This allows states to initiate amendments independently of Congress, demonstrating a mechanism for state influence in constitutional changes.

This process was established in Article V of the Constitution to maintain a balance between federal and state power, ensuring that any amendment reflects a strong agreement among both the national legislature and the states. The other options provided do not correctly represent the formal processes outlined in the Constitution. For instance, a simple majority in the Senate fails to reach the required threshold for significant constitutional changes, while presidential decrees and majority votes by state governors do not have any constitutional authority to propose amendments.