Which statement about the Mexican Senate's composition is accurate?

Which statement about the Mexican Senate's composition is accurate?

• A. All 128 seats are elected by single-member districts.
• B. 96 state-level seats are elected by the party with the most votes in each state.
• C. 32 seats are elected by nationwide proportional representation.
• D. The 96 state-level seats are elected by a mix: two by plurality in each state and one by the second-highest vote in the state, while 32 seats are elected by nationwide proportional representation.

Answer: (D)

Mexico uses a mixed electoral system for its Senate that blends geographic representation with national party strength. There are 128 senators: 96 come from the 32 states (including Mexico City), and 32 come from nationwide proportional representation. In each state, three senators are elected: the party that receives the most votes in that state gets two seats, and the party with the second-most votes in that state gets one seat. The remaining 32 seats are allocated through nationwide proportional representation to parties based on their total national vote share. This combination explains why the accurate description includes both the state-level plurality seats (two for the winner, one for the runner-up) and the nationwide PR seats. The other statements misrepresent the system by omitting either the runner-up seat, or the nationwide PR component, or by proposing all seats from single-member districts.