This article develops and tests a model of conditional status quo bias and American inequality. We find that institutional features that bias policy outcomes toward the status quo have played a central role in the path of inequality. Using time-series analysis of top income shares during the post-Depression period, we identify the Senate as a key actor in the politics of income inequality. Our findings suggest that the supermajoritarian nature of the Senate and policy stagnation, when coupled with economic and social factors that produce rising inequality, create a situation in which inequality becomes difficult to reverse.