Which case established the principle of 'one person, one vote' for legislative districts?

• A. Baker v. Carr
• B. Plessy v. Ferguson
• C. Reynolds v. Sims
• D. Brown v. Board of Education

Answer: (C)

The principle being tested is that legislative districts must be roughly equal in population so every vote carries equal weight. In Reynolds v. Sims, the Supreme Court held that state legislative districts must be apportioned on a population basis and that both houses should have districts with populations as close to equal as practicable. This applies the Equal Protection Clause of the Fourteenth Amendment to ensure one person, one vote, striking down maps where rural districts were vastly overrepresented compared with urban ones. The effect is that representation tracks population changes, giving voters in larger communities a voice proportionate to their numbers.

Baker v. Carr opened the door for court challenges to redistricting by establishing justiciability, but it is Reynolds v. Sims that meaningfully sets the one person, one vote standard. Plessy v. Ferguson and Brown v. Board of Education address segregation, not how legislative districts are drawn.