While this proposal may seem kind of dumb in the fact that it seems to ignore the interests of every party besides Prussia, Austria, and Russia I still kind of think it might have been possible to happen. Britain was at the time too busy worrying about France to care about something like this and all these 3 would be going to war with France anyway by the end of the year so they may be able to simply ignore whatever they thought. If the Czar embraced the idea he could spin the proposal as a way to strengthen the Europe empires against Napoleonic influence Especially if some of the smaller German states and the ottomans began siding more closely with France. The likely hood of this actually being agreed to and put into effect are kind of low but maybe possible, the Prussians would absolutely refuse to give up the polish corridor for one thing and I am not sure If the Austrians would be very thrilled about the deal as well especially as it destroyed the Holy Roman Empire and gave the Russians much more power. And really It wouldn't matter in the end as Napoleon would definitely use the deal as Justification to invade early and any border changes would be gotten rid of as quickly as they happened.
Napoleon wouldn't need to use the deal as an excuse to invade - the Czartoryski plan was explicitly intended as an anti-Napoleon plan and a prelude to a new coalition against France.
I feel like the ottomans would have something to say about this plan...
Also exactly what it entails with Polands borders is a bit unclear
I feel like that wikipedia quote is kind of misleading, or at least it doesn't match what I've read in articles about Czartoryski's proposals. Given the source cited is a single Britannica article from 1911, I'm not sure how accurate it is.
At the time (during the period between the end of Peace of Amiens and the 3rd Coalition), Prussia was resolutely neutral, but Britain and Russia were desperate to convince Prussia to join the coalition (both powers resented Austria at the time, and saw Prussia as a more competent alternative ally). Czartoryski, who was Foreign Minister of Russia at the time and a close friend of Tsar Alexander, had been radicalised against Napoleon by the execution of the Duc d'Enghien and Napoleon's coronation as Emperor. He saw this as an opportunity to reunite Poland (his homeland) under Russian rule, and convinced Alexander to support this plan to invade Prussia. Russia would invade Prussia and Austrian Galicia, Polish notables would cooperate with Russia and proclaim Alexander the King of Poland, and Prussia would be forced to submit both to the changing of borders and to joining the anti-French coalition. Britain saw this as a way to end Prussian neutrality and align everyone's interests against France, and thus offered Russia the 3 million pound subsidy that Britain had offered to Prussia. Austria also agreed reluctantly to the plan (which would see them surrendering Galicia in exchange for Silesia and Bavaria). I assume, if successful, this plan would have led to a Poland within its pre-Partition borders (more or less), united with Russia and controlled by the Tsar.
These plans only collapsed due to Alexander's Prussian sympathies making him delay the invasion (giving up the advantage of surprise), followed by him going directly to Berlin to meet with Friedrich Wilhelm III and proclaiming 'eternal friendship'. Pro-Prussian Russian diplomats in Berlin had also leaked the plan, which convinced Friedrich Wilhelm III to abandon his neutrality and join the Third Coalition. This Prusso-Russian alliance came too late for Austerlitz, and the war was lost before Prussia had a chance to actually join in. Prussia was so embarrassed by having chosen the wrong side of the war, and so afraid of French retaliation, that it signed the Treaty of Schoenbrunn (giving up Ansbach, Neuchatel and Cleves in exchange for a potential future annexation of Hanover, which led to Prussia joining the Fourth Coalition once France tried to give Hanover back to Britain in the 1806 Franco-British peace negotiations).
Czartoryski's plans did have an impact, in that it was the death knell for pro-Russian/pan-Slavic sentiment amongst Polish nationalists. It also led to Napoleon offering the crown of Poland to Alexander at Tilsit, but Alexander didn't want to offend Berlin, and instead the Duchy of Warsaw was established and given to the King of Saxony, with only Bialystok being given to Russia. The eventual establishment of an autonomous Congress Poland under Russian rule at the Treaty of Vienna was also a legacy of Czartoryski's influence.
Czartoryski's plans did go through a number of stages of development, so there are a lot of variants for anyone interested. Before being made Foreign Minister, he advocated a radical reorganisation of Europe on enlightenment-era pan-nationalist lines (specifically, he wanted a German confederation and an Italian confederation to act as buffer states between France and a pan-Slavic Russian Empire which rules Poland).
Czartoryski proposed a similar plan during alliance negotiations with Britain in 1804 (restored Switzerland/Sardinia/Netherlands, confederations of western German and Italian minor states, and a possible independent Balkan union, which would serve as buffer states and balancing forces in a new Westphalian system of European peace), but this was rejected and whittled down by British objections and disobedient Russian diplomats. At some point, due to the Serbian Revolution, Czartoryski proposed for the Ottoman Balkans to be turned into an independent confederation of Christian Greek/Slavic states, with Russia annexing Moldavia, Kotor, Corfu and the Straits, while France and Britain would be compensated with islands and/or other Ottoman territories - but British objections to any interference in Ottoman affairs ended these plans too. The most famous of Czartoryski's plans, and the one which came closest to success, came afterwards, proposing the invasion of Prussia and conquest of Poland. After Austerlitz, Czartoryski proposed one last plan for the Balkans and Egypt to be seized and distributed amongst the Coalition as compensation for their losses in Germany and Italy, but he had been discredited at this point, and soon Czartoryski was removed from power.
Some articles/books I read when I was looking into Czartoryski's plans for my maps:
- Prince Adam Czartoryski and Napoleonic France, 1801-1805: A Study in Political Attitudes by W.H. Zawadzki (this one has a lot of interesting details about negotiations between the great powers and plans to change European borders)
- Alexander I and Czartoryski: the Polish Question from 1801 to 1813 by Charles Morley
- Czartoryski and European Unity by M. Kukiel
- Czartoryski and Russia’s Turkish Policy by Tadeusz Swietochowski