The decennial census is foundational to our democratic society. Census population counts guide appropriations and federal funding allocations, congressional redistricting, state and local budgets, and data-driven business and research decisions. Yet despite its importance, the 2020 Census faces unprecedented threats to its accuracy. Since 2010, decennial census preparations have faced (1) underfunding leading to scaled-back testing and outreach operations, (2) innovations that promise efficient implementation but remain undertested and underdeveloped, and (3) the last-minute introduction of a citizenship question. For this reason and others, the US Government Accountability Office (GAO) has added the 2020 Census to its high-risk list of government activities in jeopardy in the coming years.