Mexico's Single-Term Presidency

Mexico's 1917 constitution bans any president from ever running again, for any term, at any point in the future. That single rule exists because of history: Porfirio Diaz ruled for over three decades through repeated reelection before the 1910 Revolution, so the new constitution made reelection impossible at the presidential level to prevent another strongman from entrenching himself. The result is the sexenio, six years and out, permanently.

Because a Mexican president can never campaign again, reelection stops working as a behavioral lever. A president cannot trade favors for future votes or build a multi-term legacy through incremental politics, so priorities get compressed into one term. Formally, the president holds real power: the ability to initiate legislation and issue decrees in some regulatory areas, command of the armed forces as commander-in-chief, and control over foreign policy including treaty negotiation, subject to Senate ratification. These powers look similar to a strong presidential system on paper.

What has changed is the informal layer sitting on top of those formal powers. Under the PRI's dominance from 1929 to 2000, the president effectively controlled the party, both chambers of Congress, and most governorships, so formal and informal power merged into near-total dominance. Since Mexico became competitive, with PAN and later MORENA winning the presidency, a president now faces an independent Congress that can be held by opposition parties, so every bill requires real negotiation. This connects directly to Mexico's legislature and judiciary: the same institutions that once rubber-stamped the president now function as actual checks.