This article argues that Mexico’s detailed and strict oversight rules for political finance, while among the most robust and praised in the world, are ultimately rendered ineffective due to recent failures of the country’s electoral justice system. Through a process of politicisation, the country’s Electoral Tribunal has increasingly used legal formalism and technicalities to reverse sanctions imposed by the National Electoral Institute (INE). The article first traces the historical evolution of Mexico’s political finance
model. Then it describes the country’s political finance framework and the INE’s sophisticated mechanisms of oversight. In addition, it provides key historical examples of sanctions and multimillion dollar fines levied on political parties in the early 2000s and 2010s. By contrasting historical
‘megafines’ with recent reversals, the paper demonstrates how procedural excuses now shield political actors – especially the ruling party – from the consequences of non-compliance.