The Uniform Small Loan Law (USLL)—the primary tool of the Russell Sage Foundation (RSF) intended to improve credit conditions for poor people in the United States during first decades of the twentieth century—created a new class of lenders who could legally make small loans at interest rates exceeding those allowed for banks. By the 1930s, about two-thirds of the states had passed the USLL. Econometric models show that urbanization, state-level economic characteristics, and the nature of a state's banking system all affected the chance of passage. That party-political affiliations had no effect is consistent with the USLL's “progressive” character. The passage of the USLL in one state, however, made passage less likely in neighboring or similar states. The evidence suggests that the RSF only imperfectly understood the political economy of the USLL, and that a different overall approach might have produced a result closer to its real aims.