Hi! I can speak to the Lost Cause revisionism. I'm a History grad student at West Chester University in Pennsylvania who has focused on the Reconstruction Era. I am currently doing research on Senator Thomas F. Bayard of Delaware, a Northern Democrat and apologist for the South during the Reconstruction Era.

Multiple voices challenged the Lost Cause revisionism almost as soon as it appeared. Americans, both North and South, rebuffed these challenges for a number of reasons. Southerners like Enoch Bank and John Mosby (a former Confederate officer), challenged the romanticizing of the secessionist movement. Mosby especially targeted the downplaying of the centrality of slavery to secession.

Obviously, (Radical) Republicans challenged a lot of the Lost Cause narratives as it appeared. Unfortunately as more centrist Republicans were elected (the Liberal Republicans, as they became known), Republican policy embraced reconciliation with the South and, concomitantly, the revised narrative of secession and the Lost Cause. The biggest EARLY anti-Lost Cause voices are fairly well known: Charles Sumner, Thaddeus Stevens. Others, like Representative George Boutwell of Massachusetts and Oliver Morton of Indiana, are less famous but lived through the entire Reconstruction and vocally opposed Southern apologists.

So-called Carpetbaggers also attempted to counteract revisionism. Albion Tourgee (judge in North Carolina) and Powell Clayton (Governor of Arkansas) wrote extensively seeking to rebuff the Lost Cause/Dunning School narratives. Mostly their own testimonies fell on deaf ears.

Finally, the most fervent anti-Lost Cause activists were black Americans. Frederick Douglass, George Washington Williams, etc. W.E.B. Du Bois's 1935 Black Reconstruction is the first historically sound rebuff to Lost Cause/Dunning School revisionism.

The biggest reasons these voices were not heard? White supremacy, economics, and the rise of the US as a world power. Lost Cause revisionism helped detach the national conscience from the centrality of the issue of slavery. It also helped alleviated Northern complicity in the survival of slavery. Economically, the Panic of 1873 reduced Northern stamina for maintaining Reconstruction policy. The Lost Cause and the Southern-apologist narrative helped ease any trepidation over abandoning the Freedmen of the South. Finally, America's entry into the world stage in the 1890s (Hawaii, Spanish American War) required the national focus to shift and depended on a reshaping of American identity to stress unity.

Great books on this?

Those Terrible Carpetbaggers by Richard Nelson Current

Race and Reunion by David Blight

A Fool's Errand by Albion Tourgee

Capitol Men by Philip Dray

Black Reconstruction by W.E.B. Du Bois

Reconstruction: America's Unfinished Revolution by Eric Foner

Reconstructions: New Perspectives on Postbellum America edited by Thomas Brown

(apologies for any grammar/stylistic errors... quarantining with two toddlers!)