The American Civil War goes wrong for the north, but the north never forgets. Eventually, the South is re-absorbed (along with Canada) in the late 1890s.
In continental Europe, the German Empire grew much larger much faster; Russia and Austria-Hungary disintegrated in the late 1890s after Russia managed to gain more land in East Asia and Austria-Hungary was more successful in the Balkans against the Ottomans in the 1870s. As a result, the German Empire was more than happy to setup MittleEuropa pretty much unopposed, with only a weak Russian Republic standing against it.
Meanwhile, Britain and America were both hurt by the rapid reorientation of Europe, and France essentially bought into the German project to gain more colonial territory. Britain responded by shifting far right and America responded with another revolution, going far left.
However, Germany's empire was very fragile, and it would take a great test of arms to hold onto it. A bitter British Empire, Ottoman Empire, Italy, Spain, and China decided to try their luck at overthrowing the German system.
France opportunistically joined Germany, and 10s of millions of dead people later, the war was over.
Now Germany is rebuilding its Eastern Empire, and both France and Germany are decentralizing their expansive colonial empires. American socialism has swallowed peripheral territories all around Europe, and the fragile Russian Republic looks ready to fall to Communism.
