Tuffy, integration WAS happening early in the 20th century. The military and all federal offices were integrated before Woodrow Wilson was elected president.
He RE-segregated them. Before Wilson blacks and whites worked side by side in government offices and in the military. Wilson ended that. The Klan had also faded to near nothingness by then. Birth of a Nation, which was essentially an ode to the Klan, then came out, and Wilson very strongly praised the movie, which he claimed was not only important for everyone to see, but historically accurate.
He was the President. And he was a former university professor and the president of Princeton University. Folks accepted what he said about the movie, flocked to it and absorbed its racist message, one Wilson himself championed.
The Negro leagues did not begin to form until nearly 1920, and by then the Klan had enjoyed the greatest growth and popularity it has ever seen, at least in part because it was not only accepted by the establishment (Wilson), but virtually blessed as a wonderful organization with great ideals.
Before the Negro leagues, black players were able to barnstorm with white players, but that was about it.