Definition
The color line is W. E. B. Du Bois's term — coined in his 1903 essay collection The Souls of Black Folk — for the racial boundary, formal and informal, that separated Black and white life in the United States. "The problem of the Twentieth Century," Du Bois wrote, "is the problem of the color-line."
The phrase names a system, not only a barrier. The color line ran through neighborhoods (where one could live), schools (where one was taught), occupations (which jobs one could hold), marriage (whom one could marry, in most states until 1967), and the law itself (which rights one could expect to have enforced).
Why it matters
How it works
Du Bois used the phrase first in 1900 at the Pan-African Conference in London, then made it the keynote of The Souls of Black Folk. He meant something broader than American segregation alone — the color line, for him, included European colonialism in Africa and Asia. Within the U.S., it captured what made Black American life distinct: the experience of being marked as outside the polity by an external sign, the experience of "double consciousness" — seeing oneself through the eyes of a society that defined you as inferior.
The line was enforced through layers. Federal law (the Three-Fifths Compromise, the fugitive slave acts, Dred Scott, Plessy v. Ferguson); state law (Black Codes, Jim Crow statutes, anti-miscegenation laws); local ordinance (sundown towns, segregated public services); informal norms (where one could shop, sit, drink, speak); and violence (lynching, the Klan, the white riots of Tulsa 1921 and Rosewood 1923) all reinforced each other.
The Great Migration was an act of negotiation with the line rather than an escape from it. The North had no Jim Crow statutes but it had redlined housing, segregated schools, and union locals that excluded Black workers. Wilkerson's three protagonists — Ida Mae Gladney in Chicago, George Starling in New York, Robert Foster in Los Angeles — each found a version of the line in their new cities, redrawn but still present.
The civil rights movement attacked the legal line and largely won. The line that survives is the informal one — visible in residential segregation indices, school demographics by ZIP code, and the persistent racial gaps in wealth, criminal-justice contact, and life expectancy.