Since the first decennial enumeration in 1790—conducted in accordance with Article I, Section 2, Clause 3, of the U.S. Constitution, or the “census clause”—the census has collected data on the racial and ethnic composition of the U.S. population. For more than 150 years, civic leaders used that information to advance discriminatory policies and maintain positions of privilege and power for the majority White population, even in the face of constitutional amendments abolishing slavery, establishing equal protection under the law, and guaranteeing voting rights for all Americans, regardless of race, ethnicity, and national origin.

But census data also became a powerful tool for overcoming the nation’s legacy of slavery, racism, and discrimination. School desegregation plans in the wake of Brown v. Board of Education, for example, relied on census race and ethnicity data to establish new school zone boundaries that would facilitate integrated learning environments. Census data objectively illuminated unequal opportunity and access to affordable housing, jobs, and institutions of higher learning, a portrait of inequality in America that helped spur passage of seminal civil rights protections.