Also, I just realized, Russia abolished serfdom at around the time the US abolished slavery, and I believe some US abolitionists looked to that as inspiration. I'll have to research that part a little bit more.
I'd noted the near-simultaneous occurrence as well. While skimming around Cassius M. Clay's* Wikipedia page, I noted Clay does seem to have been inspired by the emancipation, telling Lincoln in 1862 that he would only fight if the President promised to emancipate the slaves. Incidentally, it appears that Alexander II vowed to enter the war should Britain and France intercede on behalf of the Confederacy. Rather perplexing that as illiberal and agrarian a country as Russia would fall on the side of ending slavery and promoting industrial capitalism (in this isolated instance). I'd be forced to speculate that it might be related to the cotton trade; it was the Civil War that spurred the Russians toward Central Asia, and Uzbekistan is still a significant source of cotton, as I recall. This might be attributing false motives, however.
*Not the boxer