who is given the power to admit new 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.
Preamble to the United States Constitution The phrase "to form a more perfect Union" has been construed as referring to the shift to the Constitution from the Articles of Confederation.[71] In this transition, the "Union" was made "more perfect" by the creation of a federal government with enough power to act directly upon citizens, rather than a government with narrowly limited power that could act on citizens (e.g., by imposing taxes) only indirectly through the states.[72] Although the Preamble speaks of perfecting the "Union," and the country is called the "United States of America," the Supreme Court has interpreted the institution created as a government over the people, not an agreement between the States.[73] The phrase has also been interpreted to confirm that state nullification of any federal law,[74] dissolution of the Union,[75] or secession from it,[76] are not contemplated by the Constitution.