Final answer:
All thirteen states had to consent to amend the Articles of Confederation. The U.S. Constitution later required two-thirds of Congress and three-quarters of state legislatures for amendments.
Step-by-step explanation:
The Articles of Confederation (AOC) required a unanimous decision, meaning all thirteen states had to consent to amend the Articles. In contrast, the United States Constitution, which succeeded the Articles of Confederation, established a process for amendments that requires a two-thirds majority in both houses of Congress and ratification by three-quarters of state legislatures. The difficulty of amending the Articles of Confederation was one of the reasons why the Constitutional Convention of 1787 was held, leading to the drafting and subsequent ratification of the Constitution.