Public schools exist to educate students. Local school districts are governed by elected school boards. But only adults vote in local school board elections. I argue that these three facts are the primary cause of low academic achievement in American public schools, particularly for the most disadvantaged students. The institutions of democratic control cause unacceptably poor performance because the main concerns of adults who vote in local school board elections are not aligned with the academic needs of students. Adult interests – organized around partisanship, identity politics, employment concerns, and property values – dictate what schools do, often at the expense of academic achievement. I also argue that the existing literature, focused on the debate about the role of money and teachers’ unions in education, overlooks other major problems with public education. Finally, I also anticipate the main counterarguments to my thesis and “prebunk” them by showing why they are wrong.