The Legislatures of Mexico and Nigeria

Mexico's Congress has two chambers. The Chamber of Deputies has 500 members: 300 elected from single-member districts by plurality vote, and 200 elected through proportional representation from party lists, designed to represent population. The Senate has 128 members, mostly elected in sets of three per state plus Mexico City, with a smaller portion from a national party-list. Because the Senate represents states rather than population, it gets powers tied to national and foreign affairs that deputies do not share, most notably confirming the president's Supreme Court nominees and approving treaties.

Nigeria's National Assembly works on a similar logic. The Senate gives each of the 36 states exactly three seats, plus one for the Federal Capital Territory, Abuja, for a total of 109 seats. This flat allocation treats every state as equal regardless of population, protecting smaller states from being outvoted by giants like Lagos or Kano. The House of Representatives, by contrast, has 360 seats distributed roughly by population, so it tracks where people actually live. Like Mexico's Senate, Nigeria's Senate holds unique powers, including confirming key presidential appointments, that the House does not.

Both cases show the same design principle: a lower house tied to population protects majority rule, while an upper house tied to states or territory protects federalism and gives smaller regions a guaranteed voice. This connects directly to how executives work in these countries, since presidents in Mexico and Nigeria must negotiate with an upper chamber that cannot be outvoted just because it represents fewer people.