Made using ~1Blomma's excellent tutorial: [link]
Same setting as this CSA map [premise reposted below]: [link]
My take on a victorious CSA scenario, based on assertions that the country would turn into a banana republic or even a North Korea.
The CSA manages to eke out a victory before the Emancipation Proclamation; essentially, a TL-191 victory. However, this doesn't grant the CSA magic logistic powers, and it ends up as a backward slaveocracy that's even surpassed by Russia. The Austro-Prussian and Franco-Prussian wars are butterflied away, shaking up European power politics and maintaining the French as the dominant power in Europe.
Confederate politics goes south after an attempt to "liberate" Cuba in the 1880s leads to war with Spain, France and the US. The upper south is retaken by the US and slavery is forcibly abolished, while Texas, Louisiana and Florida gain independence thanks to French aid. This leads to an Army coup, which blames the old regime for the Confederacy's military inferiority and beginning the Confederate "tradition" of shaky military juntas. Whenever a particularly revanchist officer takes the title of "President," the United States Marines swoop in to replace him with someone more manageable.
Interestingly, at the turn of the century, the CS and US begin to work together as part of a greater British plan to form a North American buffer against France's ambitions in the New World. A great war sometime in the 1920s over some Austro-Ottoman conflict in the Balkans leads to the collapse of the Austrian, Russian and Ottoman empires while Prussia finally forms Germany. France itself falls to communist revolution, taking down most of Western Europe with her. Meanwhile, in North America, the United States moves in to fill the void left by France, becoming the regional hegemon.
There is no analogue to the Second World War, but many big wars happen across the decades. Particularly bloody conflicts are an ill-advised Russian attempt to retake the Baltics, the destruction of the Japanese Empire at the hands of the British and Americans, a French attempt to spread the revolution to the Netherlands and the rather messy fallout from the collapse of the Ottoman Empire. Nuclear weapons are developed in the 1950s, but are never used in war.
In the meanwhile, the Confederacy becomes less and less fond of their northern neighbors. The country slinks further and further away from the American sphere, but while there is some flirting with the British and Germans, the Confederates ultimately adopt isolationism. Paranoid military dictators build some of the most elaborate defensive networks seen on the planet. The Confederacy slowly evolves into an "army with a country," foregoing economic development for more military buildup. In reaction, the Americans begin troop buildups of their own, but aside from a few nutcases nobody believes that the Confederacy could ever take on the Americans without being totally demolished. Although slavery is a thing of the past and the "separation" laws were abolished in the 1990s due to extreme outside pressure, Confederate society is far from racially equal, making it one of the more infamous regimes on the planet. However, the Confederate leadership still maintains strong economic ties with the United States, and while a Confederate president would never admit it the country is effectively an appendage of American economic interests.