well if Jim Crow and such never happens, I'd say the 1880s or 1890s, the South is in the GOPs bag if the Blacks can vote and don't go north like in OTL, you got Mississippi, South Carolina and Louisiana are Black majority states, Alabama, Florida, and Georgia have 45% black population, so the deep south and New England and mid-west are all GOP strong holds, we're looking at the death of the Democratic party.