I'm convinced that you could make an argument that the Sun actually rises on the western horizon. The British wanted the buffer state, and that was for obvious reasons. They didn't get it and the US expansion continued. I admire how you reconstruct things with verbiage so that the US "dropp[ed] their war aims" but the British did not. Seems to me that from your standpoint the British were in the position to force the return of much of their former colonies. Such generous sportsmanship in negotiating a treaty to end a war is rare indeed.
Well, no, because there is a difference of events here.
What you have in 1812 is that:
- British merchants were selling weapons to Tecumseh and the associated tribes.
- An independent Indian state had strategic merit.
- But the British were not willing to go to war over it.
- Supporting it while at war, however, was a "no-brainer" decision.
- The British had war declared upon them.
- The US wanted to obtain Canada.
- They also wanted an end to Impressment (or the understanding of Impressment in the PR world which was mostly fairly different to the reality in terms of the magnitude involved).
- These were the key things which drove the war.
- In order to suppress Tecumseh's Confederacy, a war with Britain was neither necessary nor, in fact, desirable, since the support available to Tecumseh while he was allied with a Britain at war was greater than the support available to Tecumseh while he was buying things from British merchants.
- The suppression of Tecumseh's Confederacy was already largely complete by 1811 (Tippecanoe, which put an end to Tecumseh's efforts to establish a wider confederacy).
- The US declared war on Britain.
- The primary British objective in the war was for things to go back to how they were at the start of the war (that is, a white peace/Status Quo Ante).
- They got this.
- Sufficiently good battlefield performance might have allowed them to press for additional goals, and nations are never really going to run
out of ideas for war goals under those circumstances.
- But it is transparently obvious that if a nation actively declares war on you, you need to do better than
that nation is expecting to get a status quo peace. (Otherwise they would not have declared war.)
- The primary US objective in the war was for the formal end to Impressment, or the annexation of part or all of Canada, or both.
- They did not get either of these things.
- They thus
underperformed relative to their own expectations in a war they started.
And:
- If the British wanted to continue the war and seek harsher concessions, it was obviously within their means to do so; they still had a large army, a robust economy and so on.
- It was not what they wanted to do.
- If the US wanted to continue the war and seek harsher concessions, the collapse of their economy would limit their means to do so.
So the British were attacked by surprise while at war with a significant fraction of Europe, defended themselves for two years before launching a series of counterattacks, and forced a status quo peace from attackers who (obviously) wanted other significant war goals.
If the war had been started
by Britain, with an uproar over the plight of Indians being responsible, then there'd be a lot more grounds for claiming the establishment of an Indian buffer state as a significant British war aim.