The phrase is stated three times in the book — in the Forethought, in "Of Our Spiritual Strivings," and at the climax of "Of the Dawn of Freedom." Each repetition extends its scope. What might first sound like an American particular becomes a planetary diagnosis: the relations of darker to lighter peoples in Asia and Africa, in America and the islands of the sea.
Du Bois insists that the colour-line is not a regional pathology or a leftover of slavery to be waited out, but the concrete test of the republic's founding principles. The "spiritual striving" of the freedmen's sons is the travail of a people who carry the burden in the name of human opportunity itself — for if the republic cannot recognise them, it cannot claim to be the republic it professes to be.
Written in 1903, before two world wars, before decolonisation, before the long civil rights struggle, the diagnosis proved chillingly accurate. Du Bois lived to see much of the century unfold — and to argue, at the end of his life, that the colour-line had merely been redrawn rather than dissolved. The phrase outlives its century because the structure it names did.
The Forethought (1903) opens with this sentence. Du Bois had already used a version of the formulation in his 1900 address to the London Pan-African Conference.
