The U.S. Supreme Court case Davis, Secretary, State Board of Elections, et al. v. Mann et al., 1963 revolved around the issue of legislative apportionment in the state of Virginia. The appellants challenged a decision by a three-judge District Court that declared Virginia's senatorial and delegate districting laws as unconstitutional due to violation of the Equal Protection Clause under Fourteenth Amendment because they were based on geographical units rather than population distribution leading to unequal representation for citizens across districts (the principle "one person one vote"). The Supreme Court upheld this ruling stating that both houses of bicameral state legislatures must be apportioned on a population basis; thus affirming that political boundaries should provide equal representation for equal numbers of people.

In the dissenting opinion for Davis, Secretary, State Board of Elections, et al. v. Mann et al., Justice Harlan argued that the Court overstepped its boundaries by involving itself in a political issue best left to state legislatures and Congress. He contended that there was no constitutional requirement for states to adhere strictly to population-based representation; rather it was up to each individual state's discretion on how they wanted their districts drawn. Furthermore, he believed that this decision would lead to an unnecessary flood of litigation as individuals challenged district lines across the country based on perceived inequalities in representation. Lastly, he expressed concern about potential instability caused by frequent redistricting following every census report.