The Age of Brass: A Spanish AAR

[Riotkiller]

A strong success giving a key foothold in South America! I very much concur with O'Donnell in thinking this is the time to push that advantage as much as possible - for who knows when that troublesome factor of international opinion may flip again...

Quite interesting to see a weak Bolivia and an unusually strong Ecuador and Paraguay (looks like Peru never snatched Pastaza from Ecuador). Looks like there could be some tempting targets to take, as long as the Brazilians can be kept on-side.

A shame about the CSA, though a relief that the Union cores have expired. If the Union can no longer plausibly retake the CSA in full then that does mean that propping the Confederates up is a much lower priority though.

 

[ThaHoward]

Good to see that Victoria now have company as Queen-Empress!

 

[AvatarOfKhaine]

In the name of Isabella!

 

[stnylan]

Darned Confederates. What a silly decision - and not a good one for Spanish future interests. The loss of the naval battle is a concern as well.

By those blemishes are for the future. For the present Spain can hold her head high in the world.

 

[Viden]

Viden: Hah! Though does that mean you want me to attack the CSA to try and nab Florida?

Perhaps if they misbehave in the future. By now I would settle with liberating Nicaragua and defending the CSA from the obvious Yankee aggression.

And why does Peru own the Bolivian coastline?

I suppose they won it via war before Chile could do so.

 

[guillec87]

those damn' Brits... always sticking their noses in another country's backyard...

 

[GoukaRyuu]

If the US wins please have them take Nebraska and Kansas. Fix that horrendous border.

 

[Surt]

So its time, the Union will crush the Confeds if you don't help, and will stop all further intervention by Spain soon after, if you fight, I hope you bring good allies ...

 

[Southernpride]

Well let's see if the Confederacy can pull off another impossible victory like they did when they won independence.

 

[Jaimie Wolf]

Well that was quite a good read so far, hope you continue, I like your Style. Even brought me to the point of booting up my copie of VicII again, thanks for that!

 

[RossN]

Peru & Bolivia in May 1871.​

Chapter Eighteen: From South to North

The late 1860s and the first half of the 1870s were crucial ones for European affairs, but while Spain played a significant role in these events her primary focus throughout this era was drawn irresistibly to the Americas in conflicts that would see her engaged both in the South and in the North [1].

With Peru defeated the Spanish forces in South America turned their attention to Bolivia. The landlocked state was ruled by General Mariano Melgarejo, a particularly brutal and unsavory dictator. The Bolivians had no great love for the Peruvians, who had defeated them in a war two decades before and annexed what had been Bolivia's route to the sea but it is probably fair to say the popular feeling in the country was against Spanish interference in South America. War with Bolivia automatically meant war with her ally Chile, and to this combination might also be added Ecuador (not an ally of Bolivia or Chile but a thorn in the Spanish side all the same.) With the Brazilians once again allied with Spain the majority of the continent was involved in one way or the other. Argentina and Paraguay were neutral but fiercely anti-Spanish while Colombia under the conservative government of President Mariano Ospina Rodríguez was also neutral but openly pro-Spanish.

For the Marqués de Mendigorría, the continued struggle in South America owed much to his political alliance with General Leopoldo O'Donnell. The Spanish prime minister was scarcely adverse to restoring Spanish control to what he and most conservatives (and many liberals) perceived to be illegitimate revolutionary regimes but he remained anxious about events both in Europe and in North America were predictably the Confederate States were already running into trouble even with generous war subsidies from Madrid. Don Leopoldo O'Donnell on the other hand stressed that if Spanish authority in South America was to last her reconquista must be as swift as it was decisive. There might not be another opportunity to achieve victory without a piecemeal conflict.

In fact it would take more than three years for the wars to draw to a close. Bolivia, though militarily the strongest of Spain's enemies would be overrun earliest. With the Brazilians invading from the East and a decisive Spanish victory at Santa Ana on 22 February 1869 Bolivia crumbled quickly, though actual peace would be delayed until the Spanish and Brazilians defeated Chile conclusively. That would not be achieved until the Second Battle of Valparaíso on 10 April 1871 [2]. The war in Ecuador meanwhile would last all the way until April 1872. The difficulty Spain faced in this war was not the strength of the enemy - Ecuador had no standing military to speak of and her conscript soldiers, though often gallant and patriotic were poorly trained and equipped. Nor was it truly the nature of the fight - the exhausting war in the Chilean Andes with its jagged rocks and bitter winter snows had taken a graver toll on Spanish soldiers. It was simply the lack of resources Spain had available to annex Ecuador. For one thing the Brazilians were not at war with Ecuador. Technically Brazil was in alliance with Ecuador and while the government in Rio de Janeiro certainly favoured Madrid over Quito Dom Pedro was a man of his word and so maintained a strict neutrality in this clash (the Spanish, sincerely grateful for Brazilian aid elsewhere did not press the point.) With Spain faced with more 'important' wars elsewhere the Ecuadorian front remained in play for a long time and towards the end of the conflict the comparatively small Spanish forces present would be assisted by a brigade of soldiers from the Ejército real del Perú ['Royal Army of Peru'] in the first example of one of Spain's New World "dominions" coming to her aid.

In all three countries eventually forced to the peace table the outcome resembled that conducted with Peru. Bolivia, Chile and Ecuador all became quasi-independent satellites, in common union with the Spanish Crown and under a much greater degree of Spanish oversight than Mexico but still largely autonomous within their internal borders. The Viceroy(s), representing the monarch, were appointed by Madrid. In practice there was strong incentive for these men to work with the local elites to keep the peace in South America and they did not possess the sorts of dictatorial sway unsympathetic foreign observers sometimes accused them of. The events of the 1820s and 30s had proven all too well that Spain could not control half a continent with musket and bayonet alone. The promise of Spanish funding and access to Spanish markets was, at least in theory, the carrot to the military stick. Unfortunately at least in the early years scant money was available, for reasons that shall soon become clear.

The borders between the United States and the Confederate States after the armistice of April 1869.​

To no one's surprise the Confederate States were swiftly brought to the negotiating table, suing for peace on 4 April 1869, after a year of fighting. The United States demanded and received the Arizona Territory (which it had occupied during the war.) In some respects the results could have been far worse; Arizona was poor and sparsely inhabited with most of its people Spanish speaking Roman Catholics or Navajo Indians and neither group held much loyalty or love for Richmond (or Washington for that matter.) It could even be said, with a certain degree of rose tinted spectacles, that by their peace treaty of 1869 the United States legally recognised the Confederate States as a sovereign power for the first time. Still there was no way to see the surrender as anything other than a humiliating defeat. President John C. Breckinridge, concious that the Confederacy was losing the war had declined to run for a second term in the 1869 presidential election leaving his former Vice President James Longstreet to win a very narrow victory that February and face the thankless task of running the country in peacetime.

Reaction in Spain to the Confederate defeat had been muted, save perhaps for relief that the peace had been so mild. Reaction in Mexico was much more alarmed. The government in México City had assumed that their neighbours to the North would be preoccupied for a period of years. The Mexicans had never lost their desire for the portion of Chiapas still held by Guatemala. Unfortunately, Guatemala was an ally of the United States and even the currently humbled United States was more formidable than the Empire of Mexico.

The Viceroy of Mexico at this time was General Miguel Miramón. Don Miguel Miramón was ambitious and charismatic and keen to stress that Mexico was an equal partner with Spain. At a certain point Miramón had decided that Mexico would go to war against Guatemala, even at the risk of fighting the United States. He knew Mexico would not fight alone.His genius was in recognising that the government of Madrid that had refused to rescue the Confederates from their own folly would have no choice but to aid Mexico should she go to war. Isabella was Empress of Mexico and the Viceroy who had a shrewd measure of his nominal monarch's mind knew that she could not remain aloof if her throne was under threat.

The Mexican leader planned his campaign of wooing the Empress with as much strategy as overseeing the war itself. From September 1869 to January 1870 Don Miguel was in Madrid, paying a state visit, officially to help plan the future coronation of Isabella in México City. While there he took the opportunity to ply his charisma on Isabella. There is no evidence that things went further than public flattery and in any case the Viceroy had no desire simply to become a royal favourite but he did make a strong impression. For a further year he would bombard the Empress with affectionate and flattering letters from his position across the Atlantic.

Miramón was playing a dangerous game and for all his cunning patience was not his strong suite. Ideally he needed the Spanish to have finished their wars in South America but still retain their troops there. However he also had to contend with his own political rivals in Mexico, and knew that the earlier he struck the better it would be for his own position. Events to his North also played a part. The November 1868 election in the United States had seen Simon Cameron win re-election largely due to the unwillingness of the electorate to abandon a president in war time but he remained corrupt and indolent. Miramón had no desire to go to war in 1872 and see Mexico become a issue during another American election, perhaps even seeing a hardline figure triumph in Washington. Early 1871 was as late as he was prepared to wait.

On 25 February 1871 the Congreso in México City voted for war with the Republic of Guatemala, citing the same demand that they had made in the last war: the surrender of the portion of Chiapas still controlled by the Guatemalans. Very properly Miramón, as Viceroy, sent a telegram to his monarch in Madrid rather than declaring war outright.

Miramón's fateful telegram of 25 February 1871.​

The result was exactly as Don Miguel had foreseen. The Spanish government was desperate to avoid a war with the United States but the Mexican leader had so well cloaked the steps he had taken towards war that the first the Marqués de Mendigorría and General Leopoldo O'Donnell knew of it was the arrival of Miramón's laconic telegram. The monarch made her views known at once, tartly informing her ministers that of course they must support Mexico. Not only was Mexico in the right - and it had been a longstanding Spanish position that Mexico owned all Chiapas - but to abandon the Mexican government now would send a shockwave throughout Spanish America. At the very least it would mean the end of the Empire of Mexico (at least with Isabella on the throne.) Very possibly it would destroy the system of viceroys being put into place in Peru and soon to be begun in Bolivia, Chile and Ecuador.

The Marqués de Roncali, the Spanish Foreign Minister privately informed the Marqués de Mendigorría that should Spain fail to support Miramón all Spanish foreign policy for over a decade would be for naught and that in all likelihood the United States would install a pro-Washington puppet republic in México City. As furious as he was at being forced into this position by the Mexicans the prime minister went to an audience with the queen. In this terse encounter he advised her that she should declare war on Guatemala, both as Empress of Mexico and Queen of the Spains.

Spain was at war with Guatemala, and thus her allies Nicuragua, Costa Rica and the United States. But being at war did not mean the same thing as fighting. Spanish military forces in North America were negligible in 1871 and O'Donnell refused to contemplate moving men out of South America until Bolivia and Chile at least surrendered. This would take another three months of hard fighting in Chile before the war drew to a close there.

There was relatively little doubt in Spain that, if she threw all her resources at the matter, the United States could be forced to the negotiating table (Nicaragua, Costa Rica and Guatemala herself were seen as insignificant in the greater scheme of things.) The problem was that Spain was poorly positioned to fight such a massive war across the Atlantic and the help that had enabled her to fight the far more minor powers of Peru and Bolivia was absent. Of her allies Brazil would remain aloof until Ecuador was defeated [3]. Colombia, though friendly towards Spain had a treaty with both Costa Rica and Nicaragua which prevented her from joining the war. And as for Spain's most powerful friend in North America...

The defeat of 1869 had left the Confederate States sadder and wiser and many were prepared to understand why Spain had remained out of the war. The war subsidies had drawn much of the sting from Madrid's neutrality and in October 1870 the Longstreet administration had approached the Madrid government about renewing the Confederate-Spanish alliance, a move welcomed by the Marqués de Mendigorría. However the Mexican declaration of war on Guatemala and the rapid embroilment of Spain in a war with the United States confused and frustrated many in Dixie who had a hard time understanding why Spain (apparently) was willing to fight the Yankees over a slice of Central America but not for Missouri. Part of the confusion was that the relationship between Mexico and Spain and Isabella's position as Empress of the former and Queen of the latter was poorly understood by many in Richmond, not helped by the absence of a Mexican ambassador to President Longstreet and the reluctance of the Spanish ambassador to admit the tail was wagging the dog.

With the Brazilians, Colombians and Confederates all neutral - at least for the moment - Spain would have to hope Miramón had not misjudged his gamble and could hold on alone for at least a few months more.

Don Miguel Miramón, Viceroy of Mexico and architect of the Spanish-American War.
​

Footnotes:

[1] In other words it will have to wait for another chapter.

[2] The First Battle of Valparaíso was a Brazilian victory over the Chileans.

[3] Unfortunately Brazil (which otherwise would certainly join the war against the USA) can't until Ecuador is defeated because Ecuador is technically their ally. The Confederates would also probably join my war but are locked into a truce with the United States until 1874.

 

[RossN]

J_Master: I think they already used that event but I'll definitely take a look at it once the war is over (assuming I win!)

Riotkiller: Unfortunately I ended up at war with the United States anyway, so it might have been better to aid the Confederates then... still, live and learn. It is interesting the way the South American states had settled especially as my own intervention came late and only thanks to an event.

ThaHoward: Yes! If things ever settle down enough across the Atlantic I might see about that imperial coronation...

AvatarOfKhaine: Hurrah!

stnylan: I know! I really want to update my navy but upgrading my ports is taking a long time and I'm very drained on resources. Still I do have the tech for ironclads at this point.

Viden: Hah! Well, technically I am now at war with both Nicaragua and the United States...

guillec87: Very true. They are a menace!

GoukaRyuu: I admit the borders are very unsightly but I thought I better wait until the current war is over before fixing things just in case the borders change again. In theory a land exchange of Nebraska for Arizona is something I could see happening in universe.

Surt: Sadly not the case, but I will try my best!

Southernpride: well... no, but they did survive.

Jaimie Wolf: Thank you so much! I hope you continue to enjoy this!

 

[AvatarOfKhaine]

In the name of Isabella, Mexico must not fall!

 

[Viden]

It is so weird to see Mexico as female...

Anyway, it seems we have here an opportunity to finally bring peace and order to Central America. And to liberate California and Deseret once for all!

 

[ThaHoward]

Good to see order restored in south america.. as it goes for Mexico supporting them is needed. If Spain can't aid her close ally Mexico and union partner how can she then protect her dominions? Hopefully the US will seek out peace rather than a costly and bloody war over what is essentially jungles and swamps?

 

[stnylan]

Some fine work in South America - but that is a ballsy move by the Mexican government. A very nice "play" of Spain, but also one hopes not an over-estimation of Spanish might and ability.

 

[Specialist290]

Miramón, you brilliant bastard. So much could have gone badly wrong with that ploy, but you managed to make everything go just right. Well, almost everything -- there's still that little matter of a war to fight...

 

[guillec87]

you allow them a little freedom...

 

[Riotkiller]

Definitely got some strong momentum at the moment with the domino-like collapse of the South American Republics, and if a major victory over the USA can be achieved, the power of the second Reconquista may become irresistable...

 

[RossN]

Spanish cavalry scouting in Mexico.​

Chapter Nineteen: The Battle for Mexico

The war of February 1871 to October 1872 was fought mostly by the United States of America and the Kingdom of Spain, was nominally waged over a slice of Guatemala and would be decided in Costa Rica and Honduras. Naturally it was called the 'Battle for Mexico' by almost everyone.

In justice the Mexicans did suffer perhaps more than any of the involved powers, facing several bloody defeats on the field and having up to a third of their country occupied by the Americans at one point. The United States had not wished for war but having defeated the Confederates so recently the jingo feeling was still strong in Philadelphia and New York and there was deep concern over the encroachment of foreign rivals. As many troops would be committed to the invasion of Mexico as had fought in the Civil War a decade before and for a time in late 1871 the government in Washington DC openly expressed the intention to annex Sonora to punish Mexico and permanently hobble her as a power.

For the Spanish the only troops immediately available in early 1871 were those in Honduras under General Benito Asensio. Asensio commanded about twelve thousand soldiers, an mix of light cavalry and mountain artillery whose role hitherto had been as a reserve to aid the forces embroiled in South America. Asensio was under no illusions that his men could win the war unaided, but nor could he simply sit on his hands in Honduras. Faced with threats to both his south (from Costa Rica and Nicaragua) and to his north (from Guatemala) the Spanish commander marched on Guatemala. At the Battle of Guatemala City in March, Don Benito crushed the Guatemalans. After this victory the Spanish temporarily abandoned the Central American front to try and aid the Mexicans against the Americans. Asensio participated in the joint Spanish-Mexican triumph at the Battle of Rosarito in August, before his own decisive defeat at the First Battle of Nogales the following month.

The early clashes with the Americans were bloody but enlightening for the Spanish. The technology gap between the two sides was not vast; indeed most soldiers on both sides used the (French) Minié rifle, though more modern breechloaders were slowly making their way into the common infantry-man's hands. The Yankees in their heavy Prussian blue woolen uniforms and hard felt hats disdained the lightweight pinstripe blue and white 'pajamas' and straw hats used by their enemy. The Spanish, whose uniform was the result of hard won experience in the tropics claimed they could smell the enemy from a mile away as they were marinated in their own sweat. The one aspect that did genuinely distress the men from Madrid was the seemingly limitless supplies their enemy could command. American artillery could often fire three of four shots to every one Spain could command, and the food available to the common soldier from Maine or Ohio, though often bland to Spanish eyes far outpaced the scale of rations available to most Spaniards.

Theoretically the Spanish Army and the Imperial Mexican Army should have been working together. At times, such as at Rosarito they managed such a feat but often rivalries and suspicions between the two armies lingered. Many officers and men had served on opposing sides in the war of the previous decade and fights could erupt whenever the soldiers shared camp. Broken noses and grazed knuckles occasionally threatened to take more troops out of fighting condition than the conventional illness that plagued armies on the march. In one incident that left the generals aghast a... disagreement over a lady of the evening in Cócorit resulted in a duel that left a Spanish artillery captain dead and a Mexican lieutenant permanently blind.

The Second Battle of Nogales, 2 to 4 June 1872.​

A far worse outcome was the disastrous Second Battle of Nogales in June 1872. General Francisco O'Donnell, a cousin of the famed Don Leopoldo had commanded the Spanish forces shipped directly to Mexico from across the Atlantic. Francisco O'Donnell was a lean fifty year old officer whose Hibernian heritage showed in his pale complexion and stark gray eyes. An expert raider, hellbent on harrying the enemy O'Donnell had inflicted several minor defeats on the enemy and even raided as far north as San Diego, putting the fear of God in the populace of California. Unfortunately for him his relations with the Mexican Army were poor even by the standards of the war. At Nogales in Sonara, not far from the Mexican-American border he faced Edward Grant, the daring Boston born general who might have been one of the finest military men of the century. O'Donnell, counting on Mexican reinforcements that never arrived found himself attacking well fortified American lines. The result was Spain's worst defeat since Cadiz in 1848. O'Donnell managed to escape but left thousands behind as either corpses or captives [1].

Second Nogales did not knock Spain out of the war, but it did have two immediate outcomes. The first was a greater effort to work with the Mexicans. Ironically the Mexican elections of 1872 that had swept the conservatives from power in México City proved helpful. The Marqués de Mendigorría regarded José María Iglesias, the new liberal leader in the Mexican Congreso as a republican (a suspicion not without foundation) but the liberals were willing to work with the Spanish as a means to outflank Don Miguel Miramón. Miramón himself remained Viceroy but his power base had been badly eroded when his conservative coalition had been defeated at the polls.

The second result of the defeat at Nogales was to look at other routes to winning the war than simply pouring soldiers into Mexico. The end of the war with Ecuador had opened up new possibilities. Spain's two greatest allies, the Confederate States of America and the Empire of Brazil had hitherto been neutral. The Richmond government would remain neutral, but it was a stance openly biased towards Madrid. Spanish soldiers were allowed to traverse Confederate territory without fear of consequences, to the chagrin of General Grant who more than once was forced to watch his opponents disappear beyond the Rio Grande. Though there were no war subsidies as such - Dixie's economy was too frail for such a thing - Spanish and Mexican brigades could count on cheaper food and textiles along those areas of the Mexican border that remained beyond the reach of the blue uniformed armies.

Brazil had no such qualms about staying out of the war and with Ecuador now firmly in Spain's orbit the Rio government answered Madrid's request. Brazil was unlikely to supply many actual fighting men for North America (Central America was another story) but her economy was robust and her navy large if old fashioned. The Armada Real Española had already enjoyed superiority along the Atlantic coast of the United States, keeping the United States Navy rotting at anchor in Norfolk. The addition of the Brazilian Armada Imperial, the fifth largest fleet afloat turned superiority into supremacy and the Spanish government began to contemplate a direct naval landing at Washington DC to capture the American capital in one swift devastating blow.

The landings at the Potomac, September 1872.​

While all this was taking place the Central American front was not quiet. Guatemala, the nation over whom the entire war was being fought had surrendered as early as Christmas Eve 1871. The Mexicans had overrun the entire country and in such circumstances the peace demand from México City was lenient: the immediate annexation of the Chiapas region. Don Francisco de Lersundi y Hormaechea, the Captain General of Honduras represented Spain in the negotiations in the last days of 1871.

The surrender of Guatemala theoretically ended the war but the other powers were determined to fight on. Nicaragua and Costa Rica between them could field perhaps twenty thousand men and neither wished to abandon the chance to weaken Spain and Mexico.

At the start of 1872 Spain still had about thirty thousand men in South America. Ecuador still stubbornly held out, and would until April, but that still left six brigades 'free'. Not surprisingly the Marqués de Mendigorría wanted those soldiers moved to Mexico by sea to reinforce Francisco O'Donnell. Leopoldo O'Donnell stubbornly insisted on marching them to Mexico the long way, invading Costa Rica and Nicuragua en route. More than anyone else the Spanish War Minister had realised that control of the peninsula was key to the war, even beyond the nominally grander conflict being waged in Mexico. If Spain annexed Costa Rica and Nicuragua it would probably push Colombia into the war on the Spanish side; the government in Bogotá was friendly with both Madrid and Washington DC and had attempted to balance her neutrality til now. If that happened and the war was still stuck in Mexico then the Confederate States might be tempted to break their truce with the United States, and even if they did not that truce was bound to expire in 1874.

Don Leopoldo O'Donnell's strategy was a great gamble, and one that looked positively reckless after the Second Battle of Nogales. With the Americans across the border in force he had effectively reassigned more than forty thousand soldiers away from Mexico - the original eighteen thousand in Costa Rica, gradually being reinforced by twelve thousand from the now defeated Ecuador and another twelve thousand engaged in the Washington landings. Taken together these men represented nearly half the available brigades in the Americas.

In the first half of 1872 the Spanish under General Vincente Argüelles-Meres overran Costa Rica proper, taking the capital city of San José and the seaport of Puntarenas (the fall of the latter resulted in the only sea battle of the war where the Costa Rican Man-o'war Juan Mora Fernández (74-gun) and two armed clippers were sunk by a small Spanish squadron.) Reaching Honduras he crushed the Nicaraguans at Comayagua. On 18 May he defeated the Costa Rican Army in the field outside San Salvador before turning north and liberating La Cebia, in enemy hands for several weeks. At the Second Battle of San Salvador on 12 August Argüelles-Meres comprehensively defeated the last elements of the Costa Rican Army.

On 15 September after a long bombardment of the shore positions The Spanish landed troops on the west bank of the Potomac. The following morning the first artillery shells began falling on the American capital. The damage was minimal and President Simon Cameron and the rest of his government had already evacuated but within hours the Richmond newspapers would be printing the first (sensationalised) reports of Washington in flames [2].

The furthest extent of the American advance into Mexico, late 1872.​

Even as the war had arrived on the President's doorstep peace negotiations were taking place. As early as August with the collapse of Costa Rica Cameron had been sending out peace feelers through the offices of the French embassy. By 5 September the Americans were in direct contact with the Spanish and considering terms.

Cameron would forever be hounded by the popular press for the peace he would ultimately sign. The anger felt was understandable; though the United States Army had suffered reverses in the field it was still firmly in possession of Mexican territory. A potent myth would quickly develop that Cameron, never a beloved figure, had lost his nerve at the final moment and sold of the family silver.

The truth is more complicated. Cameron's stance in September 1872 was pessimistic but it wasn't out of line with the facts. The American position was gradually deteriorating. With Central America in Spanish hands Francisco O'Donnell could look forward to thousands of reinforcements, potentially including Brazilian regiments. Once installed in San José or the Nicuraguan capital of Mangua the Spanish would prove very difficult to shift. American overseas trade had dwindled to nothing as the Spanish and Brazilian fleets patrolled the sea. Even before the first cannon was fired at the Capitol the Americans had very good reasons to seek peace.

The Treaty of San Salvador was negotiated in November of that year between the governments of Spain, Mexico, Brazil, the United States, Nicaragua and Costa Rica. Spain and her allies agreed to respect the governments of Nicaragua and Costa Rica and to observe pre-war borders. Surprisingly the sole territorial exchange would be from the United States to the neutral Confederate States of America. At Spanish insistence the United States abrogated their gains in 1869, returning the Arizona Territory to the Confederacy in an exchange for monetary compensation. It was a severe humiliation for the United States and an unexpected delight for the Confederacy but the Marqués de Roncali had argued persuasively that it would prevent a new war breaking out within months: Arizona was of little value in and of itself but Dixie would fight for it [3].

Ultimately the Empire of Mexico 'won' the war at a fearful cost in lives; they had succeeded in annexing territory that they had claimed for over forty years. However the lingering effects meant that in a real way no one won. The governments in Madrid and Washington had been forced by circumstances only partially in their control to become bitter rivals and that sentiment seemed like it would linger. In some respects the war did not end in San Salvador, the weapons simply changed to diplomatic and economic influence rather than rifles and steamships.

North America After the Treaty of San Salvador, the end of 1872.​

Footnotes:

[1] The Second Battle of Nogales was the result of me trying to be a bit too clever and timing my army to arrive with a Mexican force; naturally they changed their minds at the last minute. That said the Americans having a superb leader in Grant and my dreadful luck with the dice roll played a part in the severity of the defeat.

[2] Washington had not yet fallen at the time of peace but it had almost done so.

[3] Essentially the war was decided by Costa Rica who were the leaders of the 'American' alliance in-game. In fairness the advantage of forces was with me, so I think I could have achieved something similar the hard way. As for Arizona that was chosen because the United States does not in fact have cores there.