Improving public education has long been a cornerstone of the Democratic platform. Because progressives understand that access to a quality education is the gateway to a better life, their decades-long struggle to promote equal rights and opportunity for all Americans has been deeply tied to their struggle to create an effective public school system. Over the past two decades, cities that have embraced chartering, such as New Orleans, Washington, D.C., Denver, Newark, and Indianapolis, have experienced profound student growth and school improvement. The charter formula--school-level autonomy, accountability for results, diversity of school designs, parental choice, and competition between schools--is far more effective than the centralized, bureaucratic approach that developed more than a century ago. The charter sector has created opportunity for millions of underserved children. But teachers at charter schools tend not to unionize, so as the charter sector grows, union membership shrinks. As a result, union leaders and their allies have gone to war against charters. This article traces the progressive roots of the charter school system over the past three decades and highlights the importance of preserving this system as the 2020 election approaches.