Local self-government and intergovernmental cooperation are recognized by the constitution as important to the people of the state in a bill of rights for local governments. It establishes the integrity of governmental units and boundaries, and prohibits them from being annexed to another without consent. In order for a local government or part of its territory to be annexed to another, the constitution requires that there be consent to the change by the governing board of the local governments or counties affected, and the consent by majority vote on a referendum of the people in each affected local government or county.
(d) No local government or any part of the territory thereof shall be annexed to another until the people, if any, of the territory proposed to be annexed shall have consented thereto by majority vote on a referendum and until the governing board of each local government, the area of which is affected, shall have consented thereto upon the basis of a determination that the annexation is in the over-all public interest. The consent of the governing board of a county shall be required only where a boundary of the county is affected.