Turnout: 52.66%
About this election
The midterm legislative election of 6 June 2021 renewed all 500 seats of the Chamber of Deputies halfway through López Obrador's term. Billed by the president as a referendum on the Fourth Transformation, it was the largest midterm in Mexican history. Morena remained comfortably the largest party but lost its standalone majority; only with its allies did the governing bloc keep control of the chamber — and it fell well short of the two-thirds supermajority it had sought to entrench constitutional change.
As in every Chamber election, 300 deputies were elected in single-member districts and 200 by proportional representation in five regional constituencies, for three-year terms. For 2021 the governing parties (Morena, PT, PVEM) ran as the "Juntos Hacemos Historia" coalition, while the opposition assembled the unprecedented "Va por México" alliance bringing together the historic rivals PAN, PRI and PRD against Morena. Citizens' Movement stood alone. The INE administered the vote despite repeated clashes with the president over its budget and independence.
The campaign was the most violent in recent memory, with dozens of candidates and political figures killed. López Obrador, though not on the ballot, dominated the contest through his daily press conferences, framing it as a choice between his movement and a "conservative" restoration. The opposition concentrated on Mexico City, where discontent had grown after a metro-line overpass collapsed weeks before the vote, and on defending the autonomous institutions the president had attacked.
Morena won 35.3% of the vote and 198 seats — down from its 2018 peak and short of a majority on its own. With the PVEM (43 seats) and the PT (37), the Juntos Hacemos Historia coalition retained a working majority of around 278. The PAN recovered to 114 seats, the PRI took 70 and the PRD 15; Citizens' Movement won 23. Crucially, the opposition denied the government the two-thirds needed for unilateral constitutional reform. The opposition also broke Morena's grip on much of western Mexico City.
The result blunted López Obrador's most ambitious constitutional projects, including an electricity-sector reform that subsequently failed for want of a supermajority. It confirmed, however, that Morena had become the natural party of government across most of the country, holding or winning a swathe of governorships the same cycle. The balance struck in 2021 — Morena dominant but constrained — framed the run-up to the 2024 general election, when the movement would again reach for the supermajority that eluded it.
Compiled and reviewed by Bartłomiej Paruzel, Election Data Analyst, from official results. See our data methodology.