Rapid tuition increases over the last few decades have made public institutions much less affordable than they once were. This and other policy changes may be affecting college enrollment rates across the country. This article examines how student preparation and college supply interact with the usual factors of tuition, financial aid, and family background to explain state by state variation in public college enrollment rates among Black, Hispanic, and White youth over the 1990s. This study finds that rapid tuition increases over the 1990s, changes in federal need-based aid, and steady increases in merit-based financial aid cannot explain variation in public college enrollment rates during the 1990s. What can help explain this variation are a state's expenditures on state need-based aid and its investment in public higher education capacity. The study also finds that differences in the high school completion rate of Hispanic youth, among states and over time, help explain patterns of Hispanic enrollment in public postsecondary institutions. The article concludes that the current policy emphasis of maintaining low tuition may not be the best use of public subsidies in terms of promoting equitable access to higher education. (Contains 3 figures and 4 tables.)