Do corruption scandals affect the internal dynamics of political parties and, if so, under what conditions? In this paper, I argue that corruption scandals can destabilize political parties by diminishing electoral support and triggering leadership crises. Utilizing a unique dataset of Mexican legislators (2006-2024), I employ a staggered difference-in-differences design to examine the causal impact of corruption scandals on party switching and party discipline. Results indicate a modest but statistically significant increase in both behaviors following scandals. This effect, however, is not universal across different electoral rules: Mexico's mixed member system shows that scandals affect only deputies that elected via plurality, but not legislators elected by closed-list proportional representation. This research expands our understanding of corruption scandals, demonstrating their ability to not only influence voter behavior and electoral outcomes but also reshape the internal dynamics of political parties by altering the behavior of party members.