This paper contributes to our understanding of American education politics by exploring when and why states redistribute K-12 education dollars to poorer schools. It does so by examining three explanations for intra-state changes in progressivity: court-ordered finance reforms, political trends, and demographic changes. Using state-level data from 1995-2016, we find mixed evidence that progressivity increased following a court-ordered school finance overhaul. Rather, we show that changes in progressivity were most consistently tied to changes in student demography: as students became poorer, or more racially diverse, lawmakers created less progressive finance systems. The paper concludes by discussing what these findings mean for advocates seeking to protect and advance gains in education spending progressivity.