which established the guidelines by which new states would be added to the united states
Admission to the Union The Admission to the Union Clause of the United States Constitution, oftentimes called the New States Clause, and found at Article IV, Section 3, Clause 1, authorizes the Congress to admit new states into the United States beyond the thirteen already in existence at the time the Constitution went into effect.
State constitution (United States) The Tenth Amendment to the United States Constitution, part of the Bill of Rights, provides that "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." The Guarantee Clause of Article 4 of the Constitution states that "The United States shall guarantee to every State in this Union a Republican Form of Government." These two provisions indicate states did not surrender their wide latitude to adopt a constitution, the fundamental documents of state law, when the U.S. Constitution was adopted.