Political Reform (LOPPE) — Left Parties Legalized

Interior Minister Jesús Reyes Heroles under President López Portillo implemented the Ley Federal de Organizaciones Políticas y Procesos Electorales (LOPPE), legalizing the Communist Party (PCM) and other left parties for the first time. The reform granted conditional registration and proportional representation seats in Congress, allowing limited political pluralism while maintaining PRI control. It was the first significant electoral opening.