One of the cliches is that Europe conquered the world because European superpowers had mastered the art of turning local tribes against each other and choosing the right local allies to aid them when they used European armies to hold territory. From the French allying with local Arabs to defeat the Tuareg in Algeria to the Dutch selling weapons to multiple clans in Indonesia to make a profit and wait for the local clans to weaken each other before they come in to take over the various islands and the British building up alliances in South Asia between the most powerful Muslim and Hindu empires to avoid unnecessary destructive fighting and so they could invade and take over weaker Indian empires, its a common cliche that a major factor in colonized people being subjugated was that they couldn't unite together to fight back the far superior European forces.
However there is one thing that confuses me: Why couldn't European superpowers use this against each other? I mean as I read about European history I am surprised how many of the European superpowers that we know today such as the Netherlands once consisted of multiple different ethnicities who had their own cultures and customs and even own specific languages. In France alone there were the Vendees, the Normans, the Bretons, the Occitan, the Catalans, and the Basques. Furthermore much of the wars in the Medieval Ages were over a small city-state or specific kingdom conquering the rest of the territory that would become the modern states that we see today on the map. For example so many wars were fought in England as far as the 17th century alone just to see the country be united under a single dynasty. Prior to that England's multiple different regions were divided by ethnic lines and nobles fought each other in an attempt to unite the country.
So I am wondering why say the Spanish were unsuccessful at uniting with some Basque French and Vendees to use as allies during their wars with France? Why couldn't the Bavarians await for Prussia to be weakened from its wars with Russia and than attack to take over Northern Germany at the right moment? Or why couldn't the British stir up discontent in Sweden to create a civil war in which different local towns decide to revolt against the Swedish monarchy?
Its not just among superpowers in the region that I'm confused about. Even conquering quite weak small nations such as say Bulgaria and Moldova, I rarely see the divide and conquer policy working. Belgium for example is much smaller and weaker in comparison to even Netherlands but the Belgians had historically been difficult to divide. Romania was a divided nation yet the Ottomans had such difficulty conquering them that they had to settle for tributary state and negotiate with a favorable ruler. The Ottoman could not pick say the Wallachians or some other ethnic group or city state in the country to serve as a proxy conqueror and later puppet state. Despite being subjugated by the Ottomans, neither Austria nor Russia could create the conditions for Bulgarians to have vicious in-fighting that would leave Bulgaria as easy pickings.
Why is this? What makes Europe so much more difficult to use divide and conquer despite being arguably just as disunited as the rest of the world? Its even arguable that the same European superpowers had a harder time keeping their own nations united than say creating a colonial outposts in Mexico or putting a puppet government in China! I mean there were riots in parts of England in the 18th century as Britain was trying to buy off Indian empires and put a stabilize protectorate. Ditto with France in Haiti and Vietnam, where they also had to contend with the dissatisfaction of various factions of the French Revolution and the instable change in governments (not to mention invasions from other European superpowers). Even after Spain solidified its self as an empire overseas, there was always trouble with the ethnic regions in the country that often put a blow in colonial expeditions.
Yet despite all this Europe could never use the divide and conquer on itself. What makes it so difficult despite Europe at times being far more disorganized than say conquering Indochina (which the French could do with minimal intervention) or holding Egypt as a protectorate (which didn't even need a war since Egypt was already united by a puppet ruler who favored Britain)? I mean why couldn't Austria even repeat the successes the Ottomans had in holding regions with multiple ethnic groups that hate each other and was always a powder keg?
I mean with how disunited Europe was, its so surprising the Japanese couldn't see an opportunity to take the Philippines for themselves. Or that the organized Vietnamese nation states (who used gunpowder canons) couldn't attack isolated Dutch outposts in Indonesia for their taking. Or why Korea couldn't take over Siberia when Russia was too busy fighting wars in Europe to defend their border there.
I mean there are multiple organized North African states. Yet not one of them could convince Italian city states to ally up with them to take lands together and share the rewards. Its only the Ottomans who could successfully use divide and conquer on Europe (and ironically on regions that the European superpowers themselves had a difficult time stabilizing such as Yugoslavia).
Why is there such a paradox regarding Divide and Conquer, colonialism, and uniting Europe?
Short answer is that they did, but of course this sub hates short answers so I will elaborate.
When we talk about tribes being compared too ethnic groups, I think a more proper analogy could be lordship pledging too one side or the other. An example of this being used was the Dutch Revolt, some might consider it a tad bit late but nonetheless, several lords and local leaders didn't like Hapsburg rule, and were prompted and supported by the English and French in their eventually successful revolt and separation from the Hapsburg line.
If you think of William the Silent and Maurice of Sassau (leaders of the Dutch Revolt) as tribes, with their Revolt supported by the English, we see a very similar tactic that would arise during the colonial era, this then went to further weaken Spain which England had not been on the best of terms as of late and forward their goals of becoming more powerful.
Another example of this tactic was the Hundred Years War, where the English, seeing divide in succession of the French monarchy, soon became involved, propping up their current King Edward lll of the House of Plantagent, and soon he amd his English advisors began to try to convince nobles to fight for his right too secession of the French throne, using mostly coercion to gain their support. This then led too the Hundred Years War, which turned France into a broken and war torn state for the time coming. And while in the end the English efforts were not enough and Edward lll remained King of England alone and lost lands in Gascony, however they were able to prevent the French from backing any more Scottish Rebellions (where the French had used similar tactics, using the stances of Scottish lords and supporting their rebellions with various aids from coin too supplies, too advisor's and troops.) I can elaborate further on that situation but I think I have adequately answered that these tactics were used.
Now going deeper into your question, there are questions on why these conflicts did not end with annexation, or colonization of the conquered people, and for this there are a plethora of reasons, a major reason would be the papacy, if they did not support a war, it would be hard to actually be difficult to completely integrate your lands, and if they did this brings in the issue of family ties too the monarchs and their right too the land, which taking drastic action of dethroning the current dynasty completely could bring a lot more countries into the conflict, another major reason and the last I will list was ethnic and religious groups rarely getting along, and completely throwing enemy groups together under one crown, after the country and government just went through a war, would sparsely work out.
To get around this, it was typically done that either the current monarch, or a relative of theirs would marry in or take over as the monarch of the country. This allowed them too marry into the line or be adopted into the dynasty, which would not upset the papacy and nearby monarchs, and it allowed these different groups as well as economies to stay separate.
We see this strategy used with William the Conquerer's invasion of England, where he kept England completely separate from his home province of Normandy, he could switch his treasuries from one side too the other, whichever needed more funding, the English and French were never forced to get along, and he married supporters too members of Edward's family and his own family too other English nobles to give himself basis of a claim too the French throne, such as the marriage of King Williams neice, Judith of Adelaide being married too the Anglo-saxon lord and ally of William, and Earl Waltheof of Northumbria, as well as the proposal of marriage one of Williams daughters too Edwin of Mercia.
So overall simply marrying into the line or placing a figurehead in charge was much cleaner than just completely annexing the territory and throwing all the different groups together after violently fighting, and telling them to hug it out. It also would of had a smaller chance of angering the clergy and your new neighbours.