The defeat was hardly novel. From the Civil War to the end of the [nineteenth] century not a single Democrat in Congress, North or South, ever voted for a single piece of civil rights legislation. . . .
Northern and Southern whites now reunited under the banner of white supremacy. In the 1890s, Memorial Day celebrations organized by Union League members no longer stressed the need for vigilance against Southern attempts to overthrow the Union victory. Often they invited Southerners to speak, who admitted they had been wrong to secede but right to oppose "Negro domination." In 1891 [Henry Cabot] Lodge suggested that the U.S. should keep out "Slovacks" from Eastern Europe because they represented "races most alien to the body of the American people," and he did not mean African American people. . . . The Republican Party lost what little authority it still had to improve the lot of minority races.
These were not the Democratic and Republican parties as we know them today; they flipped almost completely in the latter part of the twentieth century. The party of Lincoln is now today as racist and reactionary as were the Democrats of the South, of Reconstruction, and of the era of legal segregation -- roughly 1880-1950.
What's important to note, I think, is that despite the Union victory on the battlefields, there was insufficient backbone to impose the underlying terms of that victory on the defeated Confederacy. When those chickens came home to roost after the second world war and the modern (?) civil rights era was launched, there was still not enough spine to make the laws stick.
In certain aspects, especially in and through popular culture, a more permanent victory was achieved. But we still have a very, very, very long way to go, and the road is not getting any easier.