Evolving from the Judiciary Act of 1789, which designated the attorney general (AG) as legal advisor to Congress and the president, the Department of Justice (DOJ) crystallized in 1870. It included a solicitor general (SG) to represent the government before the Supreme Court, began enforcing civil liberties and rights, interstate commerce, and immigration statutes and, by 1872, administering federal prisons. It expanded in the twentieth century, adding a deputy and an associate AG; eight divisions, for example the Civil Rights Division (CRD); seven police affiliates, among them the Federal Bureau of Investigation (FBI); thirty-five offices such as the Office of Tribal Justice; and five special agencies such as the National Drug Intelligence Center. Today DOJ is one of the largest departments, employing more than 30,000 people.

Civil and human rights advocates look to CRD; it enforces laws banning discrimination based on race, ethnicity, gender, religion, language, disability, and sexual orientation. Formerly the Civil Liberties Unit (1939) and Civil Rights Section (1941), it became CRD by the Civil Rights Act of 1957, which added an assistant AG and advisory US Commission on Civil Rights. The black freedom movement and southern white backlash tested the Division, as did enforcement of the Civil and Voting Rights Acts of 1960, 1964, and 1965. The crucial 1964 act not only barred unequal voter registration criteria, segregated schools and accommodations, and employment bias, but also instituted the Community Relations Service (CRS) to assist state, local, and school officials in resolving disputes. Racial riots, fueled by tensions over desegregation or injustices such as police brutality, broke out in 314 cities ca. 1963–67. By request, CRS sends conciliators into communities. Moreover, CRD implements the Fair Housing Act (1968), Equal Credit Opportunity Act (1974), Americans with Disabilities Act (1990), and Voting Rights Act (renewed a fourth time in 2006). It protects absentee, aged, and disabled voters; “institutionalized persons”; equal access to public clinics; victims of police misconduct; and immigrants.

CRS helps citizens negotiate their differences and develop mechanisms to defuse racial-ethnic tensions, as well as promote tolerance, diversity, and inclusion. In 2007, after a cross burned on the front lawn of a Cortlandt, New York black family, creating fear, CRS facilitated dialogue between law enforcement, schools, city officials, and civic leaders that restored calm.