Ad Astra Per Aspera
A dystopic space opera series with shades of military science fiction, written by rvbomally. What's so allohistorical about it then, you ask? Well, it is actually set in an alternate history, with a PoD in the second half of the 19th century.
The point of divergence is when Senator Edmund G. Ross of Kansas votes to convict President Andrew Johnson, as opposed to voting against conviction as per OTL. This propels the Radical Republicans into power, whose heavy-handed approach to Reconstruction creates a more violent backlash. This results in a cycle of violence and increased repression that soon consumes the United States. By the 1940s, the United States is a de facto presidential dictatorship and after a crisis in the 1960s, the “Old Republic” is abolished in favor of the American Empire.
The American Empire, along with the Soviet Union and German Empire, dominate the world. Faster-than-light travel is invented in 2047 by the Germans and soon these three empires expand through the stars. An unstable peace reigns until the Collapse, a cataclysmic war, in the 2240s. This destroys the three empires and after centuries of instability, three other superpowers rise up to replace them: the Coalition of Western Republics, Conseil of Workers' Systems and the United Technocracies of Man. The three superpowers compete and at times cooperate throughout the galaxy in order to pursue their ultimate interest: power.
Be warned, this TL is bleak… and far from having clear-cut good guys and bad guys… To sum it up via rvbomally's signature : “Feeling cheerful? Read Ad Astra Per Aspera and lose a little bit more faith in humanity!”
You can read it here.
Has its own (very incomplete) wiki here.
The Tv Tropes entry can be found here.