I know that after Napoleon's final defeat, the Bourbon's were recrowned. The first one (Louis XVIII) was fairly moderate and seemed to be interested in knitting the country back together, and the second one (Charles X) was super conservative and led to another revolution.
After defeating the French armies, why didnt the UK or another of the Allies attempt to directly administrate the conquered French people, and/or incorporate it directly into their already established boundaries? Was it just too expensive? Or too difficult?
Why go through all that war and bloodshed and difficulty, only to walk right out of France again leaving everything politically unstable and primed for yet another revolution that could have all kinds of negative impacts to sorrounding nations?
Cheers
It wasn't really feasible or desirable to control a land of thirty million people by force, least of all to a country committed to economy and maintaining the "balance of power", when a ready regime was at hand hostile to both revolutionary republicanism and bonapartism.
Britain's regular army strength had fallen to just 50,000 before the war, allowing maintenance of the island realm's crucial naval lead while keeping defence spending to a manageable £4-5m. While army numbers had shot up to over 200,000 in the war, distaste for the outlays involved meant that a prolonged occupation would have to involve other powers - Austria, Prussia and possibly Russia - enhancing the strategic position of whichever took part. And eliminating one rival to strengthen others was anathema to British policy which sought to prevent anyone else dominating western Europe.
Nor was the assent of Europe's other continental monarchies for such an approach a foregone conclusion: Austria and Prussia were no keener than Britain on seeing the other installed in Paris depsite their recent alliance, and for them France under a weakened version of the overthrown dynasty was as likely to become an ally as a foe, whether against rival powers or the threat of revolution. And indeed by 1818 its rulers were fully restored to the fold, even being permitted to put down Spain's constitutionalist movement five years later, an intervention that would have triggered general war in past centuries.
For all their faults and past quarrels with Britain and others, the Bourbons were by far the better option, deeply unsympathetic to either of the regimes with which Britain had just spent over twenty years at war, and now obliged to accept some degree of constitutional limitation in place of their former absolute power.