The Third Section of the Fourteenth Amendment was added to the Constitution after the Civil War to keep former Confederates out of the government.
The idea was to prevent backsliding.
It didn't work because, by the late 1890s, the government and Supreme Court were stuffed full of Confederate sympathizers who rolled back the advances made during Reconstruction and gave us racial segregation.
You can keep out the insurrectionists but not the insurrection sympathizers.
frustratedphagocytosis