Answer:
Explanation:
Article IV section 3 of the constitution mandates congress to vote on how a new state is to be formed. I do not know the exact terms of how a state is created as a sovereign body, but I suspect any new state would have to go through what Hawaii and Alaska went. These were territories that were not carved out of an existing state so the problem was not complicated by two states feuding over where the boundary would be.
Recently Puerto Rico had a non binding referendum on this very question. I don't know what was decided.
It's the Federal Government in the form of congress. The territory has to be in favor of statehood.
