Answer: A confederation.
Step-by-step explanation:
A confederation is the union of various states that unite for a specific purpose and delegate the powder to a central government. Confederations are often created in critical situations to make faster decisions intergovernmental.
For example, in America, the original 13 states signed the "Articles of Confederation" which are considered the first constitution of the republic, it was created to unite the 13 states and claim independence from England.
I hope this information can help you.