Idaho Code § 42-3319
The governor of the state of Idaho is hereby authorized to appoint a commission of five (5) members, of which the director of the department of water resources shall be one (1), to represent the state of Idaho on a joint commission to be composed of commissioners representing the states of Washington, Oregon, Wyoming, Montana, Utah, Nevada and Idaho, and a commissioner that may be appointed by the president of the United States, to be constituted by said states for the purpose of negotiating and entering into a compact or compacts, agreement or agreements, among the states, or so many of them, not less than five (5), as shall agree thereto, with the consent of congress, respecting the lawful diversion, distribution, and further utilization and disposition of the waters of the Columbia River and all streams tributary thereto, including the Snake River, with due regard to vested rights, mutual benefits and equitable apportionment, and fixing and determining a method of regulation, administration and control of said river, and its tributaries; provided, however, that any compact or agreement so entered into on behalf of said states shall not be binding or obligatory upon any of said states or citizens thereof until and unless the same shall have been ratified and approved by the legislatures of at least five (5) of the states, including the states of Washington, Oregon, Montana and Idaho and by the congress of the United States.
Idaho Code § 42-3319