How many states had to approve the Articles of Confederation?

The Articles of Confederation, which served as the first constitution of the United States, required the approval, or ratification, of all thirteen original states before it could go into effect. This unanimity was a tall order and necessitated considerable compromise and negotiation, as each state had its own interests to protect.

The Articles of Confederation defined the first governmental structure of the United States of America, which took the form of a confederation of sovereign states. Under the Articles, the states retained most of their power and independence, with the national (federal) government having limited authority, primarily over diplomacy and the conduct of war.

Because of this requirement for unanimous consent, it took a significant amount of time for all thirteen states to ratify the Articles. They were initially proposed in 1777, during the American Revolution, but weren't fully ratified until 1781. A particular point of contention that delayed ratification revolved around western land claims by several states, which were resolved by those states ceding their claims to the federal government, enabling the remaining states to move forward with ratification.

The requirement of unanimous approval for amendments proved to be one of the weaknesses of the Articles of Confederation, as it was nearly impossible to get all the states to agree to changes. This issue, among others, led to the convening of the Constitutional Convention in 1787 and the subsequent creation of the Constitution of the United States, which replaced the Articles of Confederation. The Constitution provided for a more practical method for amendment, requiring a supermajority rather than unanimity, which is still the process in use today.