To what extent does partisanship bias copartisans' responses to corruption? While existing research shows that partisanship can shield politicians from the consequences of corruption, the conditions under which this varies remain unclear. I argue that partisanship's effect on corruption voting depends on whether corruption is targeted (when the corrupt actor belongs to the voter's preferred party) or systemic (when the electorate perceives corruption to be widespread). These contexts activate different processes: copartisan bias in candidate evaluation and the weakening of partisanship's behavioral shielding effect. Using a survey experiment in Brazil and public opinion data from 17 Latin American countries (2008--2018), I find that copartisans express significantly greater support for a candidate accused of corruption when their party is implicated. However, as systemic corruption increases, they become less likely to support their party when it is in power and more likely to consider opposition alternatives. These findings show that copartisan bias in favor of accused politicians is conditional and can become fragile under certain circumstances.

Incumbents often hold power even after voters withdraw support. I argue that whether vote loss translates into office loss depends on the extent to which the anti-incumbent vote fragments across opposition candidates under electoral rules that do not require voters to coordinate around one challenger. I test this argument with a shock to royalty transfers to oil-dependent municipalities in Brazil, where most mayoral elections are decided by single-round plurality. Using a difference-in-differences design, I show that incumbents lost votes, yet their likelihood of removal was unaffected. I argue that the shock drew more candidates into the race, splitting the opposition vote and fostering incumbent survival. Combining difference-in-differences and instrumental variables, I demonstrate that additional challengers reduced incumbents' vote shares without unseating them, and that voters fragmented their support across these alternatives. Therefore, whether withdrawn support costs incumbents office depends on the structure of competition and the rules that shape it.