Idaho constitution
Article XII
Section 1

The
legislature shall provide by general laws for the incorporation, organization and
classification of the cities and towns, in proportion to the population, which laws
may be altered, amended, or repealed by the general laws. Cities and towns
heretofore incorporated, may become organized under such general laws, whenever
a majority of the electors at a general election, shall so determine, under such
provisions therefore as may be made by the legislature.