I tried, for fun with some friends, to set up the conditions to make Napoleon don't get at war with Russia, so that the Spanish ulcer would not be so decisive.
The result of it all was that as long as Napoleon lived, the remaining European absolute monarchies threw coalition after coalition, for one or other detonant.
Our idea was that Alexander never got to be Tsar, and Paul I survived. Russia, allied with Napoleon, meant the crush of Austria and Prussia and the establishment of a fairly stable liberal government in Spain, which would be the hardest situation Napoleon should face.
We set up two English attempts of disembarking in Europe (one in Spain, which would lead to a long and hasting war between Napoleon and the liberals against Fernando VII's defendants and the reactionaries; and one in Italy, which Murat would defeat), and several rebellions in Austria. Poland would be free, which Russia would accept in exchange for key parts of the Ottoman Empire.
Russia would start to feel the problem of being an absolute opressive feudal empire allied with a liberal enlightened monarchy: rebellion, nationalsm, revanchism...
At this point, my friends and I were divided. Should Russia de drowned into rebellion, leading Napoleon to become a little paranoid, making his rule not so enlightened...? Or would this just be a long internal struggle for Russia, which would last decades, but would not affect much of Tzar Paul's aggenda?
Because in 1825, we found another big turning point: the Greeks claim for freedom. Napoleon is the garant of freedom, but he also rules over a multicultural empire. Should he help the Greeks or should he ignore them...?
If Russia doesn't fall apart soon, they would still want France's help to get the Bosphorus, and so Greece would be free, but the Greeks would want Istanbul as well...
The problem is that, when we get to this point, most of it doesn't matter anymore, since it becomes a tale in which you can do what you want.
But four things are sure, from my point of view:
- Nationalism rises for sure, its bases are set even before 1789, but with the French Revolution, they are undeniable. Joseph tried to act enlightened in Spain, much like Carlos III, but many Spaniards just didn't want him, however good for them he was. I don't discard a good propaganda work from the ruling borbonic elites, but still: nationalism is irrational. And you can see it even nowadays. The period 1820-1850 would be full of troubles and turmoil for Napoleon and for Napoleon II.
- If Napoleon doesn't destroy the Prussian and Austrian monarchies, there will be colaition after coalition against him, for as long as he may live.
- The Colonies. Would France help Spain recover the colonies? Would France want more colonies? We're getting to the point in which colonies are important for prestige, but most of them are pretty useless. African colonies were never profitable. Only the Caribbean and American colonies, as well as India and Indonesia, were still profitable colonies.
- Napoleon could not land in Britain.