- What is the international political goal?
- What are the military forces required to achieve that goal?
- What are the economic costs of raising, deploying, and sustaining those forces?
- What are the domestic political alliances needed to achieve 1-3, above?
- How likely is 1-4, above, to come about, in any universe resembling the one we live in?
Absent thermonuclear weapons in the Nineteenth Century, good luck.
Best,
Ok Here goes.
1.After the revolution Britain decides that the continued existence of the USA is a stain on British History and all efforts should be made to expunge said stain.
2.During the 1780s and 1790s Britain builds up its armies in Canada. It still develops a trade empire but all is channelled into building forces in Canada and also building up the Navy even more than OTL.
3. After Napoleon comes out on top in the French Revolution, Britain comes to an agreement he has a free hand in Europe and leaves Britain and her territories alone. Yes it is dealing with the devil but the US must be expunged from history.
4. 1803 Britain makes the Louisiana Purchase. It offers Napoleon a price he cannot refuse.
5. 1804 onwards Britain builds up its forces in Louisiana as well as Canada.
6. 1812 war takes place. Invasion from Canada and Louisiana, blockade by larger RN
7. 1814 US surrenders
Is this likely -definitely not in a reality near us, but it has occurred somewhere in another quantum reality, much as there is one in which by 1812 the US has all Canada and by 1850 it has all Mexico.