Research shows that discontent with established parties emerges when they offer similar policies. But why do voters punish the political establishment—even when parties differ ideologically? I conceptualize support for outsiders and invalid voting as two forms of protest voting, ways citizens reject the establishment. I argue that convergence in poor performance, repeated failures by different mainstream incumbents, causes both behaviors. This clarifies how poor performance translates into protest voting: both the mainstream incumbent and opposition must be discredited by past performance. I focus on three dimensions of performance: corruption, economic management, and public service provision. Using survey experiments in Argentina and Chile, I show that convergence in poor performance across these dimensions causes protest voting—regardless of policy differences. Poor incumbent performance alone is insufficient to trigger these outcomes. Notably, voters punish convergence in poor performance more strongly than policy convergence, underscoring that support for mainstream parties requires not only distinct platforms but also competent governance.