Germany, Russia, the United States, and Britain, all allied, all dystopic.
How could the world end up under the prying eyes of these four gargantuan states?
The point of departure from OTL is more of a cluster of differences, all during the Napoleonic Wars; amongst smaller things, the Americans gain full control of the Lousiana Purchase, Francis II never dissolves the Holy Roman Empire and rather effectively stalls out the French in central Germany (not forever) Tsar Alexander I of Russia is forced from Saint Petersburg by Napoleon after Polotsk is a Russian loss, America joins the fight against the French in Europe and in North America, and lastly Napoleon successfully launches an invasion of England (not victorious, but it brings the Coalition to the negotiating table).
At said negotiating table in Magdeburg, Napoleon is assassinated by a contingent of Prussian and Austrian soldiers, those left in power of the Napoleonic realm are suddenly under renewed assault, and the war ends in a blood grind across the French countryside until Paris is pulverized to the point that the catacombs beneath can be seen from above.
From 1817, the butterflies flap. The longer and bloodier war led to the renunciation of Orthodox Christianity as the state religion of the Russian Empire, with a new, Slavic faith ariving only comparable to OTL LaVeyan Satanism, the case being that the rapidly liberalizing Russian government and the people couldn't believe God could allow such violence.
In the Holy Roman Empire, a dual centralization begins from the north and the south, with an unprecedented alliance between Prussia and Austria eventually leading to dynastic union, political union, and the sudden realization that by the mid-1850's the House of Hapsburg-Hohenzollern had established a hereditary and autocratic imperial dynasty over the Empire (which by then had dropped the Holy Roman, and was now officially called the Empire of the German Nation).
In Britain, reactionary attitudes amongst the populace led to the election of a similarly reactionary government; thus progress went slowly, almost fascistically, with universal suffrage only for white citizens and Asiatics by 1912; coloreds (Africans and Native Americans are 'serfs' working for industrial and agricultural combines across the federal and socialistic British Imperial Federation.)
Meanwhile in the United States of America, a continued sense of jingoistic expansion and frontier culture soon fermented itself at the pinnacle of American fundamentals, and like its British mother America was also raciall stratified; Although legally free, Asiatics such as the Japanese and Indians built the railroads and canals of the west, served as soldiers during the Mexican, Centralian, and Colombian Wars, and were thus granted suffrage under the watchful eyes of their Caucasian overlords. They voted for the single Union Party, because it was the only party, not because it had no competition, simply because the competition had no real support base. Prussian militarism, Austrian administration (better here, if violent at times), and Russian zealousness characterized the American people.
Although these nations reacted to the horrors of the Napoleonic Wars differently, they all stood aside one another in an unofficial alliance that ran the world. Colonialism, the white mans burden, and the rise of the modern era brought with it nationalism, socialism, and advances in technology unparelled by any other point in history. By 1900 the world was carved up into vast empires and the old order was falling; first the Ottomans, then even the Chinese, the oldest of the nations!
Either side of the global power system needed to strike first, because that which won would go forth to enforce conservative dominance on the New World Order.
Unfortunately for Napoleons heirs and their few allies, they could not match the raw power of the reigning Quadrarchy, and although not crushed into powder, found themselves suddenly sidelined into nonexistence, territories and colonies taken, the regime collapsing for years on end before reconsolidation, and the only thing saving them, oddly enough, was the fact that the reigning German Kaiser, poised in negotiations to completely dismember eastern France and render the very nation unsustainable, died. His rather... Americanized daughter thus took over as Kaiserin, and recognizing the corrupt and adhoc system ruling the German Nation from Prague, was lenient on Le Empereur.
Purging corruption and centralizing power in the style of an enlightened monarch, the new Kaiserin valiantly transformed the nation through force into a burgeoning social democracy. But altogether she was still an autocrat, and when the Bavarian and Hungarian nobles rebelled as the corrupt Imperial system disappeared after the war, they were crushed under jackboot and treads, to the general roar of German crowds.
Now things are tense. The Kaiserin and the Tsar grow closer, two forms of radical atheism and autocratic might converging across continents, and in a bedroom.
The Americans and British find it uneasy, especially with rumors of a Russo-German political and dynastic union. The idea of a Eurasian Empire as centralized and powerful as their own suddenly ruling 1/3rd of the world is unsettling.