who has the right 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.
Privileges and Immunities Clause The Privileges and Immunities Clause (U.S. Constitution, Article IV, Section 2, Clause 1, also known as the Comity Clause) prevents a state from treating citizens of other states in a discriminatory manner. Additionally, a right of interstate travel may plausibly be inferred from the clause.