Which case extended the 'one person, one vote' principle to state senate and house districts?

• A. Baker v. Carr
• B. Near v. Minnesota
• C. Citizens United v. FEC
• D. Reynolds v. Sims

Answer: (D)

The main idea is that votes must carry equal weight, and Reynolds v. Sims made that true for state legislatures. The Court ruled that under the 14th Amendment, state Senate and House districts must be roughly equal in population, so no group of voters is systematically overrepresented or underrepresented. This provides a constitutional standard that when states redraw district lines after a census, districts should be as close to equal in population as practicable.

This decision built on the idea from Baker v. Carr that redistricting challenges are justiciable by federal courts, but Reynolds goes further by specifying the equal-population requirement for both chambers of a state legislature. It’s different from cases like Near v. Minnesota, which deals with prior restraint of the press, or Citizens United v. FEC, which concerns campaign finance. For context, a separate case later extended the same principle to congressional districts, but the item in question is about state legislatures, where Reynolds is the essential ruling.