Baker v. Carr (1962), the U.S. Supreme Court overruled prior decisions and held that the apportionment of legislative districts was a justiciable question (i.e., one that could be decided by courts). Following Baker v. Carr, lawsuits were instituted in at least 30 states challenging existing legislative apportionment. The Supreme Court decided six of these cases together as Reynolds v. Sims in 1964.
Reynolds v. Sims challenged Alabama’s apportionment of seats in the state legislature because it underrepresented urban populations. For example, Mobile County, with a population of over 300,000, had three seats in the lower house, while Bullock County, with a population of under 14,000, had two seats. Under Baker v. Carr, this sort of malapportionment was justiciable; the question was what constitutional standard to apply in deciding the issue. Baker v. Carr had left this question open, but at least suggested a flexible approach. In Reynolds v. Sims, however, Chief Justice Earl Warren rejected the consideration of local, social, political, and economic interests, and insisted on a strict “one person, one vote” formula, thus requiring almost all the states to change their own constitutions to reflect this mathematical standard.
The decision in Reynolds engendered a strong and immediate political reaction. Thirty-two state legislatures passed resolutions calling for a constitutional convention to overturn Reynolds v. Sims, provisions for a constitutional amendment to overturn the decision were introduced in both the Senate and the House, and legislation was introduced to prevent the Supreme Court from hearing cases involving legislative apportionment. All of these efforts failed, however, and federal courts continue to play a crucial role in all aspects of legislative apportionment.