In the last decade, many political conflicts over K-12 education in the United States have increasingly divided along party lines. While it may seem like this development represents a sudden and surprising departure from a long-standing tradition of bipartisanship, I argue that the politics of education has been gradually growing more exposed to partisan conflict over a much longer period of time. This manuscript is part of a larger book-length project exploring the causes and consequences of inter-party political disputes over K-12 education. Here I examine the history of K-12 school governance in the U.S. from the revolutionary era to the present, focusing on the changing institutional arenas where education policymaking happens and the changing cast of political actors participating in the policymaking process. Over the course of decades and even centuries, the center of gravity of K-12 education policy has shifted toward political venues where partisan considerations play a more significant role. [This manuscript is a draft chapter from "The Long Division: How the Politics of Education Became Partisan," which is under contract with Oxford University Press but not yet accepted for publication.]