Thinking of it. Maybe you could play some kind of clandestine intervention in the CW. The Russians certainly have a rich history when it comes to intelligence services. Prussians ... not so much. This would make it more like a skirmish game than mass battle.
Or you have to rewrite the whole history. Could be fun too.
Tsarist Police swap the Gettysburg Address for a slightly modified copy of the Protocols of the Elders of Zion, thus projecting the Republican Party 180 years into its future.
The Okhrana hacks the telegraph system and spreads 'fake news' about the 1860 election. John Breckenridge is the somewhat surprised winner.
The Okhrana spreads a rumour that Lincoln is the head of a secret paedophile ring run by the illuminati and centered on a tavern in downtown Washington. John Wilkes Booth bursts into said tavern and shoots the bartender.