The Baker v. Carr (1962) decision of the US Supreme Court established the principle of "one man, one vote", requiring state legislatures to redistrict to bring Congressional apportionment in line with decennial censuses. It also required both houses of state legislatures to be based on population for representation and not geographic districts such as counties. This case arose out of a lawsuit challenging the longstanding rural bias of apportionment of seats in the Tennessee legislature. After decades in which urban populations had been underrepresented in many state legislatures, this significant ruling led to an increased (and proportional) prominence in state politics by urban and, eventually, suburban, legislators and statewide officeholders in relation to their population within the state. The ruling also applied to numerous other states long controlled by rural minorities, such as Alabama, Vermont, and Montana.

Which 1962 US Supreme Court ruling forced states to realign their voting districts to reflect census findings?