Say would there be a second wave of socialism because we still have the president before Teddy Roosevelt to worry about since he came in by corruption
the collapse of the confederacy vindicates the general 1st Internationale consensus of “yup, landowners are literal cancer,” so i’d say that with this substantial additional development that is this more-radical civil war, either Socialism/Syndicalism ITTL is going to have a lot more traction and general appeal, or Georgism is going to become synonymous with “liberal." I'm not even getting into the specifics of exactly how Marxian Thought would be altered ITTL, because that's another 3 paragraphs fit for it's own post.
and with all of this going on simultaneous to the development of Socialist Thought in Europe, the entire event would considerably alter the way that these major ideologies form. with the more radical direction the American Electorate is with the increasingly-Radical Republican Party, the traditional party of Labour-Aristocracy would become one of Welfare-Corporatism. Sure, the Chinese Exclusion Act is still happening (with biracial political support to "prevent the devaluation of our labor via the importation of foreign orientals en-masse" or some unreasonably racist but still labor-related in reasoning) but with segregation being seen as more of a "southern" (derogatory ITTL) thing, the shift in stance that both parties took due to the segregation of southern-state primary elections would not exist, as neither would suffrage for many ex-confederates ITTL.
the most realistic scenario for this TL's policial situation in regards to race and policy, funnily enough, is that of the Republican Union in the "What Maddness Is This: Redux" TL, in which the Republican Union is a de-facto ultranationalist herrenvolk totalitarian democracy, yet their ultranationalism is nearly civic-nationalist in how it is for Americans of every race, the only catch being that an American is a "human", and they have an interesting definition of what a "human" is. (spoilers: it doesn't include the irish.)
Corporatism, in the Anti-Revolutionary Paternalistic Conservatism practiced by Bismark, General Grant, and Disraeli is poised to really take off, albeit with a slightly less racist and more Georgist outlook in policy.
ethnic cleansing campaigns that coincided with colonial expansions in Africa after the ITTL US Civil War would become politically-untenable for many european parlimentarians with the altered, more euroskeptic US Foreign Policy and the public backlash when the papers report it as "atrocities committed by the [insert colonizing country here] against the natives in [name of colony] comparable only with the massacres of Blacks by the barbarous Southrons during the American Civil War."
essentially, when Bebel takes his stand against German Imperial Atrocities (if German Colonization still even happens in any similar way ITTL), he wouldn't be booed, instead, the SPD would supermajority-sweep the Reichstag, along with any other Social-Democratic party in the metropole of any other European Empire when the reports of atrocities in the colonies start coming in.
anything resembling what the Confederacy would have appeared to be for the vast majority of people at that period is tainted by that association, so there is no way for Brazil to have that large of a slave population, let alone the continued institution of slavery, past 1870 at latest.
unlike in our timeline, i predict that ITTL, it would be recognized earlier & by many more that "racism is bad," but not because it's bad, but because you look like a Southron while doing so.