The United States Constitution which was completed on September 17, 1787 with its adoption by the Constitutional Convention in Philadelphia, Pennsylvania, and was later ratified by special conventions in each state is the supreme law of the United States of America. It created a federal government to operate that union, and also a federal union of sovereign states. It replaced the less defined union that had existed under the Articles of Confederation. The United States Constitution took effect on March 4, 1789 and has served as a model for the constitutions of numerous other nations. The Constitution of the United States of America is the oldest federal constitution in current use.
Our forefathers who wrote the constitution saw the need for a process to amend the constitution if necessary and wrote this into the constitution itself which is Article Five of the constitution. It establishes two methods of proposing amendments, by either Congress or by a national convention requested by the states.
Under the first method, Congress can propose an amendment by a two-thirds vote of the Senate and of the House of Representatives. Under the second method, Congress must call a national convention for the purpose of considering amendments when two-thirds of the state legislatures "apply" to Congress for such a convention. Only the first method which is a proposal by Congress has been used. Once proposed whether submitted by a national convention or by Congress amendments must then be ratified by three-fourths of the states to take effect. Article Five gives Congress the option of requiring ratification by state legislatures or by special conventions assembled in the states. Article Five has only one limitation on the amending power which is that no amendment can deprive a state of its equal representation in the Senate without that state's consent.