Which case established the principle of "one person, one vote" for congressional districts under the Equal Protection Clause?

• A. Baker v. Carr (1962)
• B. Reynolds v. Sims (1964)
• C. Dickerson v. United States (2000)
• D. Shelby County v. Holder (2013)

Answer: (A)

The main idea being tested is that, under the Equal Protection Clause, districts must be drawn so that each vote has roughly the same weight. This is the “one person, one vote” principle.

Baker v. Carr establishes that redistricting disputes are justiciable in federal courts, meaning the Supreme Court can hear cases about how districts are drawn. It doesn’t itself set the population-equality standard.

Reynolds v. Sims then extends that principle to state legislative districts, holding that these districts must be apportioned roughly by population so that one person’s vote is not devalued compared to another’s.

The case that directly applies the equal-population rule to congressional districts (the U.S. House) is Wesberry v. Sanders, which requires essentially equal populations among congressional districts. That exact case isn’t in the list, so none of the listed options perfectly answers the question as stated. Among the choices, the closest discussion about apportionment is Reynolds v. Sims for state legislatures, while Baker v. Carr is about whether redistricting cases can be heard at all, and the others concern unrelated topics.