Underinvestment in transit, and electoral accountability: a spatial approach to the Metro line 12 collapse in Mexico City

Abstract

On May 3rd, 2021, a segment of Mexico City’s Metro Line 12 collapsed, killing 25 people and disrupting mobility for thousands. This disaster sparked public debate about political responsibility, infrastructure quality, and urban governance in Mexico. This tragedy, which has not been studied by others, led to the following question: What was the impact of the collapse of Metro Line 12 on electoral outcomes in Mexico City during the 2021 and 2024 elections? Previous literature on accountability shows that voters may punish incumbents after disasters, but often fail to assign blame accurately due to partisanship, poor information, or populist discourse. While “blind retrospection” and partisan filtering are well-documented, little empirical research has studied how infrastructure failures in urban transit affect multi-level electoral accountability. This case provides a rare opportunity to study electoral accountability in response to an infrastructure failure in a dense urban context under a populist regime. Using a spatial natural experiment framework, the study compares electoral sections near the collapse site with similar unaffected areas to estimate causal effects. The empirical strategy leverages detailed electoral and census data, modelling proportional changes in party support through simultaneous equations. The incumbent alliance experienced consistent and statistically significant losses across all elections, with vote share declines between 4.5% and 12.9% in affected areas. The backlash was strongest in local races, particularly mayoral contests, despite mayors lacking direct responsibility for the Metro system. Accountability was real but misdirected: voters punished local officials more than higher-level actors who held greater institutional responsibility. Early losses (2018–2021) favored the main opposition, while the third party gained more in the later period (2021–2024). These findings show that in urban democracies, service failures can drive political change—even in contexts of populist narrative control. The collapse of Metro Line 12 illustrates that neglecting public infrastructure carries a tangible political cost: despite efforts to deflect blame, voters responded with measurable electoral punishment, particularly at the local level. This underscores the need for clear attribution of responsibility and stronger accountability mechanisms to uphold democratic governance.