Final answer:
Signature indicates intent to examine and consider ratification, which is formal approval typically by a legislative body, whereas accession is how a state not initially involved can join a treaty. For the U.S. Constitution, ratification by nine states was required for it to take effect, a process completed in June 1788.
Step-by-step explanation:
Differences between Signature, Accession, and Ratification
Signature, accession, and ratification are all terms related to the process by which countries and states agree to become parties to an international treaty or agreement, or in the case of the U.S. Constitution, how it was adopted by the states. Signature refers to the act of a representative of a country signing a treaty, indicating its intent to examine the treaty further and consider ratification, which is the formal approval of an agreement, typically by a nation's legislative body. Accession is a method by which a state that did not participate in the negotiation and signing of a treaty can still become a party to it later on.
The U.S. Constitution required ratification to come into effect, a process different from the amendments to the Articles of Confederation that required unanimous consent. Instead, Article VII of the Constitution stated that only nine states needed to ratify the document for it to take effect. After rigorous debates in various state conventions and the promise of a Bill of Rights, the Constitution was ratified in June 1788 when New Hampshire, the ninth state, gave its approval.