Honestly i can see the RU abandoning Germania to its destiny. Considering how badly the war against Gran Colombia and its allies is going, i doubt Steele will be able to help Kapp's regime. I imagine he will simply say that Germania's persecution of jews makes it unworthy of being a RU's ally rather than simply admitting he is unable to help one of his fascist allies however
Originally I'd believed that the Eurofascists would organize a Pearl-Harbor on the Europans to draw the RU away from South America and into the Old World, only for the scheme to backfire horribly. Nap's since stated that the upcoming wars will remain mostly separate, so that's seeming less likely. The great trial the Eurofascists end up going through may be generational change, figuring out how to replace their Strong Man founders (Churchill will be very old come the 40s and 50s, and Kapp died of cancer in 1922 at age 63 OTL) with people who can also keep their states together and capably serve Oswald's future aims.
It seems pretty likely that they will face such a defeat. West Germania, being a tinpot fascist dictatorship, won't want to let Germany remain disunited; and East Germania is not going to let West Germania conquer it. And East Germania has a big friend.
Russia is a country of absolutely enormous potential. In OTL, a powerful and united Germany, after successfully conquering most of the European continent, fought Russia. Russia had suffered under years of Stalin purging the best and brightest, wrecking the country's infrastructure and infusing it with paranoia, turning its army into a hollow shell deprived of its best commanders. In addition, Stalin, in possibly his stupidest of many stupid decisions, trusted Hitler not to invade; so, despite defectors frantically warning the Russians that the Germans were coming, Stalin ignored them, and thus the Germans attacked with total strategic surprise and made huge advances into Russian territory with incoherent opposition and destroyed much of the Russian air force on the ground. It's hard to exaggerate how cataclsymically badly Stalin's amazing combination of incompetence—blind paranoia towards his own men, and blind trust towards (of all people!) Adolf Hitler—sabotaged the Soviet Union's war effort; if not for Stalin, the USSR would be much better off. It was pretty much the best set-up for the war that Russia's enemy could possibly have in any universe. Those were circumstances so unbelievably contrived to make Russia likelier to lose that if any fiction/AH author came up with them, we'd hold our noses and laugh at them for years for such a ridiculous extreme piece of wankery.
And yet even with all of that, Russia still won.
To add to this, Russia's friends bring quite a bit to the table. Between them, East Germania and Poland make up most of the population/industry/resources/area of the former Nordreich, and, owing to the indigenous origins of their revolutions, they are allies and not puppets. So even before getting to Russia, an invader from the west will have to chew through states/armies/partisans who actually want to block those advances and have the resources to do it, all while buying Russia time to mobilize and send help. A Barbarossa-style surprise is completely impossible. I certainly wouldn't consider the Eurofascists a match for the Illuminists any way, but it really seems like even a united Catholic bloc would run into trouble. I don't think Napoleon I even had a Russian campaign TTL, Britain's self-destruction simply made it so a proper coalition would be impossible and Nap worked things out with the Tsar at the World Congresses. So as far as anyone TTL knows, the most recent example of an invasion of Russia is... the Great Northern War. Yikes. But there's still ways for a Catholic-Illuminist war to end in something other than an Illuminist win:
1) Catholics win with the help of collaborators. It beggars belief, but somehow the Nazis were helped along by thousands of
Soviet volunteers (a separate category from the POW-slaves) for their war efforts. And this continued as late as Vlasov's defection in 1944, even as the Nazis were whomped on every front. Why? Certainly few (if any) believed in the Nazi ideal for Russia-- but it seems they instead believed Germany could be used now and discarded later, or that it would be possible to give a right-wing Russia a place within a fascist continental order. Hypothetically, if the Germans had not aimed for Slavic genocide (even if it would contradict Lebensraum) and been more capable of taking advantage of anti-Stalin or anti-Soviet sentiment, at the very least these Russian SS units could have perhaps been quite a bit larger and more capable of independent action...
Unfortunately, von Braunau hates Slavs near as much as OTL because of his experiences in the war against Viktor. Napoleon V may be able to restrain this tendency, but we still have no idea if he even regains meaningful supremacy over the Germans again. But if somehow they're able to present a united front and appeal to the submerged Russian right-wingers on the basis of restoring religiosity and the collaborative spirit of the World Congresses, they can at least leave behind a Second Russian Civil War even if they are forced to evacuate. Internal dissension, whether tarred with the "collaborationist" brush or not, is the biggest threat to Illuminist survival. Signing Brest-Litovsk never stopped the Bolsheviks from taking over Russia. And while the USSR was never successfully invaded OTL, it never needed to be.
2) Catholics win/stalemate by opening up a secondary front. The Persians are probably the most useful short-term (can support Muslim revolts and make
vast swathes of the Russian hinterland ungovernable, can force Russia to split its forces, can link up with Europa for a joint offensive on Stalingrad or something) but useless long term (the void opened up in Northeast Asia by a Russian collapse can't be filled by Persia, and presents a golden opportunity for RU expeditions out of Japan). The Chinese are still a smouldering wreck but at least hold the promise of being an effective block on RU ambitions in the East... someday. But I think opening up new fronts would ultimately be less helpful than it sounds: an alliance of Europa with a religious rival and/or with a country that feels itself to have been used by the Westerners and then left to Viktor's furies will never be the most sustainable of arrangements. Inevitably poor coordination (partly out of the massive distances involved, partly out of submerged hostility) in any permutation (EU-PR, EU-CN, EU-PR-CN, EU-RU) of anti-Russian alliance gives the Illuminists all the more latitude for action.
Naturally, these both require various degrees of "rolling 20s" on the part of Paris. It may be that Russia, along with Brazil/South America generally, have important roles to play postwar as serial frustrations to the Big Two and as inspirations to the oppressed peoples of Africa and Asia.
