One thing to note is that different strategic decisions will result in different requirements and decisions. I see the Kingdom of Hawaii becoming a British client state, and Britain perhaps "purchasing" the Galapagos Islands off Spain.
In the Caribbean, Spain retains Santo Domingo as well as Cuba and Puerto Rico, but of course its main focus is on Granada (Colombia-Venezuela) and on Peru (Peru-Ecuador).
We are looking at the best part of five decades between the solution of the South and Central American wars, and the period of the dream, 1875. The status of the Guyanas needs to be ascertained in this. I think in 1815 France is going to demand the return of their colonial holdings, but acquiesce in the loss of Holland's to Britain, thus enlarging directly British Guyana.
Britain is also going to assert a direct formal protectorate over Miskitia, as US complaints can go hang.
I see Tejas going the same way as OTL, with American settlers eventually forming a critical mass and declaring independence from Mexico. However, in this ATL's 1835 what happens then? Britain is going to be inclined to uphold the Mexico of Emperor Leopoldo, but not to the point of giving aid, only to that of preventing US intervention. However, British rhetoric is going to come up against the fact that there is nothing that can be done to prevent unofficial American aid from flooding into Texas - volunteers, supplies etc. This is going to raise the tensions between Britain and the USA dangerously.
Imperial Mexico is going to be somewhat more competent than that of Santa Anna, and won't be hamstrung by having their forces led into battle by the head of state - in fact, somewhat amusingly Leopoldo may well send Santa Anna as commander of the army, but it will be a better army and there will be less political division behind it. I see Britain as wanting to find a solution in Mexico's interests that nevertheless could help with their own, and the idea of an autonomous Texas under Mexican suzerainty, but open to independent British penetration may well appeal to London. It would also be a kick in the head for the Americans.
British-American tensions are going to be felt elsewhere too - in the Red River, in the case of Fort Astoria, and in Northern Maine, all of which over the course of a couple of decades would add to the rivalry between the two. Britain is not going to cede any territory to the USA, nor any rights, whilst the US is going to continue to push.
Of course, one area that is going to be key is Florida, which in 1814 is Spanish and thus forming a part of the restored domain of Ferdinand VII, a restored domain remember that Britain has vital interests in upholding. The British-American War does not end until 1815, with the Battle of New Orleans, but this time British defeat is not going to be assuaged by their being able to focus on a final campaign against Napoleon and an invasion of the European continent. That war is done too, and its aftermath is now the focus of British policy.
Thus the attempt by American settlers/merchants to separate West Florida from the Spanish crown and petition for entry into the USA is going to come as a crisis in British-American relations. Short of direct action, which could lead to war with the USA, Britain can't act to undo the secession, however much she might like to, but in its aftermath they can certainly act to build up Spanish government in the rest of Florida.
British money, administrative expertise and veterans from the Peninsular campaigns would be available to help turn Florida into a better-run and viable colony, bringing the Seminole under control, and protecting what is basically an undefended frontier with the USA. Thus there is no Jacksonian invasion, and Florida remains as part of Spain, many of the British veterans eventually settling there, especially those with Spanish families.
Near-war in 1840 over the Northern Maine border pushes Britain and the USA to the brink, and it only takes a spark to ignite. With Texas remaining as an autonomous satellite of Mexico, the cause for direct conflict between the USA and Mexico is somewhat obviated, or more likely definitely in second place behind the causes for direct conflict between the USA and Britain
Oregon of course is the spark, it is the mid 1840s and by now it is simply too much effort to avoid a war.
BRITISH-AMERICAN WAR, 1846-1848
Britain fights this war alone, though with the benevolent neutrality of Leopoldo's Mexico and of Spain, now under Isabella II.
Britain has built up a significant naval presence in the Pacific, which compliments their position in the Atlantic and Caribbean, ensuring command of the seas. Britain is thus going to be blockading American trade off New Orleans, and off New England, Virginia etc. One worry for Britain is going to be a reverse influx of volunteers from Texas into the USA, despite Mexico forbidding such actions.
France is also going to be a worry, but it could certainly be in French interests to watch two of its major rivals battle each other to exhaustion. As in the ACW of OTL it will probably provide ship building, loans etc but not directly intervene, thus allowing American blockade runners and commerce raiders to operate out of European waters. The USA also has a Mediterranean Squadron, the successor of Decatur, and this is going to have some role to play, although it is more likely to be in disrupting British trade in that sea than in successfully running the Straits of Gibraltar.
I'm not going to do a blow by blow account as this is background on the strategic level, rather than the timeline itself. Its filling in the gaps, er gaping holes!
I'm going to be controversial and say that this war is a draw, but one that solves things as the resultant peace accepts and confirms territorial boundaries - for Britain, the USA confirms their possession of N Maine, the Red River and Seattle, but for the USA the boundary is otherwise set at the parallel, and de facto US control of areas it contests with Mexico in the Plains is accepted by Britain.
The end of the British-American War runs into a period of continual crises for the Empire of Mexico, Leopoldo's authority at home having been somewhat damaged by what many see as the betrayal of Britain over the Great Plains, and severely strained by the Californian Crisis. Here prospectors and adventurers from many nations have rushed to the gold fields, overwhelming the Mexican authorities ability to deal with them and effectively running their own communities albeit in a rough and violent way.
The British Pacific fleet, fresh from securing Seattle in the recent war, lands Marines which co-operate with Mexican authorities in restoring order around San Francisco.
Mexico is busy with another series of wars in Central America, putting down secessionist movements in Costa Rica and Nicaragua, and also in trying to deal with the aftermath of the British-American War in Texas where the veterans who had volunteered for American service have now returned home to radicalise the population.
When a full-scale revolt breaks out in California, and Britain has to retire its Marines in the face of it, it soon becomes clear that a critical mass of prospectors led by American adventurers have gained control of the province. Britain is reluctant to field an army, only just recovering from the expenditure of the British-American War, whilst Mexico cannot afford one, even with the taking on of further British loans, since it has to push the war in Central America to a conclusion.
When the Bear Flag Republic, as the Californian secessionists name themselves, calls upon the USA to recognise their independence, Britain approaches the other powers to convene a congress to deal with the matter as one of international importance. With France and Russia acquiescing, and Bavaria offering to act as an Honest Broker, the California Committee meets in Havana, Cuba, and debates the issue.
As American goods are now finding their way across the Rockies into California, and it is strongly suspected that these include arms and ammunition, a coercive solution looks less and less attractive. Eventually the powers agree that California should be independent, under a joint guarantee. Mexico protests loudly but there never was any realistic hope of a Texan style solution of giving self-government but retaining Mexican oversight, since this latter is clearly gone and Mexico is not in a position to restore it.
Britain, France, Russia and the USA, albeit with the latter acting reluctantly, issue a Joint Guarantee of Californian Independence, reserving the rights of the powers acting in concert to intervene, and of their individual consulates to act in the interests of their populations. The Californian border is set by a commission under Bavarian auspices, excluding San Diego which has remained under Mexican control.
This blow to Mexican pride is somewhat ameliorated when the war in Central America is brought to a successful conclusion, but the end of the period of Mexican crises is not over yet.
TEXAN INDEPENDENCE
The protocol of the late 1830s guaranteeing Texan self-rule and autonomy, ie virtual independence whilst retaining Mexican suzerainty, has been pushed to the brink by both the British-American War and its aftermath where veterans, radicalised by their time with the US army against the British, return home and push for full independence.
The events in California provide a further push in this direction, and by 1852 there is a groundswell of support for a complete break with Mexico. Since the end of the British-American War, Mexican officials and commissions have had a much harder time of it in Texas, and now a national boycott is launched, effectively blanking all residual Mexican rights, and taking all remaining powers into Texan hands.
This Texas is better off financially than its OTL equivalent, the period of Mexican suzerainty having kept it within the trading framework of Leopoldo's empire, whilst British investment into Texas, although the subject of much ire in the aftermath of the British-American War, has provided a measure of industrialisation and financial security. British companies thus have a relatively strong stake in the Texan economy, and with British merchants and industrialists always strongly represented in parliament in London, their interests are a natural concern of the British governnment.
Fresh from the twin outcomes of losing California and retaining Central America, Mexico is in a mood to fight for its rights in Texas, but the USA makes it very clear that any such move would be seen as tantamount to a declaration of war, and Britain, having only made peace with the USA a handful of years before, is in no mood to fight a second war against them, this time on Mexico's behalf.
As Britain's position becomes clear, there are riots against British interests in Mexico City, and when the Imperial Guard move to suppress them there is a revolution, led by liberal elements of the regular army, that succeeds in overthrowing and imprisoning Emperor Leopoldo. Crown Prince Ferdinand was in Vera Cruz, where he is a naval officer, although shore-based, and Britain moves quickly to secure his person, landing Marines from the Caribbean fleet to "aid him" in taking control of the immediate area.
It soon becomes clear that the rebels in Mexico City lack any general support, especially amongst the establishment, and in their desperation they turn to arming the populace, thus bringing the spectre of a return to revolutionary war back to Mexico. Britain makes an agreement with Ferdinand to restore him to his throne (the rebels have got his father to abdicate under pressure, and neither Ferdinand nor London is that concerned to get this rescinded). In return, Ferdinand will agree to the full independence of Texas.
Ferdinand readily signs the agreement, and under his theoretical command, an army heavy with British Marines, and British colonial troops from Jamaica and Miskitia, advances from Vera Cruz towards Mexico City. At the same time, the Northern Army of Mexico which had been standing on the Texan border turns and advances South towards the capital, causing a flurry of contacts until the British are able to establish that it is acting in the name of Ferdinand, and not the rebels.
Almost by the by, the Convention of Galveston sees Mexico, Britain and the USA sign a treaty recognising that Texas has full independence, and that none of the three signatories has any special or pre-eminent position.
The rebels in Mexico City are crushed, the emaciated but hardy ex-Emperor Leopoldo released from confinement, and Ferdinand officially crowned as Emperor Ferdinand II of Mexico in the capital's largest cathedral. Leopoldo retires to Austria to live on an estate that the Emperor in Vienna grants to him in his retirement.
Best Regards
Grey Wolf
