A? is a signed and approved agreement between nations.

A treaty is a signed and approved agreement between nations.

Explanation:

An international treaty is a legal norm of an international nature, binding and obligatory for the nations that sign it, normally written by subjects of international law and that is governed by it, which may consist of one or more legal instruments and its denomination being indifferent. As an agreement it always implies the minimum attendance of two sides.   For example, the rulers of each country meet to agree about their country limits so as not to have problems with their territories.

i would say that the politicial parties from state to state varies.