How can we explain cases in which effective social policies become neglected by policymakers and citizens alike? Highly effective policies reduce the visibility of the social problems they address (e.g., poverty, poor health, inequality), thereby creating the illusion that the problem has been solved. As a result, beneficiaries may become less politically active, as the urgency that once motivated mobilization declines, and voters may similarly shift their attention toward other issues. These dynamics, in turn, create opportunities for opponents (e.g., austerity advocates, science skeptics) to argue that the policy is no longer necessary or has become too costly. Political support for a social policy may therefore erode because it succeeded, not because it failed. This study investigates this curse of highly effective social policies by developing a theoretical model that captures these self-undermining dynamics and generates several unintuitive predictions about the relationship between a policy’s effectiveness and the temporal evolution of public support and funding.