America's economic future depends in large part on the quality of the nation's public education. Education increases productivity, sparks innovation, and boosts the economic competitiveness. Not surprisingly, the American public thinks that there should be greater investments in education, with polls showing strong and growing support for increased spending. There are of course many reasons but a key, though often overlooked, piece of the explanation is the decline of the American middle class. Societies with a strong middle class make greater investments in public goods such as education, which helps fuel their future economic success. To help quantify the importance of a strong middle class to making investments in education, the authors examined in detail educational spending in all 50 states over the past two decades--the entire period for which complete data are available. They find that a weaker middle class is associated with significantly lower levels of education spending, controlling for other factors that affect education spending such as state income levels, the percentage of minorities in a state, and the age distribution of the state. This paper argues that a stronger middle class is likely to be good for the nation's educational system. And improving education in the United States would be good for the economy. Appended are: (1) Data; (2) Models; and (3) Results. (Contains 73 endnotes.)