I'm sure there've been other Lincoln Lives threads, just use the search function.
Considering how lenient his plan to reconstruct the South was, I'd imagine that we'd see a drastic split in the Republican Party between Lincoln and other moderationists and those who favor more radical measures against the southern states. If the South re-enters the Union quicker, and with more political power, we may see a much more politically powerful Bible Belt/Black Belt, meaning a higher influence of both the religious "right" and maybe even earlier black politicians in high offices.