The US annexes all of Mexico in 1848

Futurist

Ad Honoris
May 2014
23,547
SoCal
What would have happened had expansionist fever reached an especially high level in the US in 1847-1848 (much more so than in real life) and the US would have thus annexed all of Mexico in 1848? How would this have affected subsequent developments in the US--such as the debate over slavery, the American Civil War, industrialization, the US economy in general, immigration, race relations, et cetera?

For the record, my own thoughts is that a US annexation of Mexico wouldn't help the slave states very much since AFAIK most of Mexico is unsuitable for agriculture that relies on slavery--such as cotton planting. Race relations would certainly be interesting since the US would have a much larger Meszito and Native American population from the 1840s onwards. This could perhaps trigger earlier racial anxiety among US whites--thus perhaps leading to earlier large-scale support for immigration restrictions. Opening up the US's gates in the late 20th century could also be more of a problem in this scenario since White Americans might be much more likely to quickly see a demographic threat from this in this scenario. I also expect the US government to launch various incentives to reduce the Mexican fertility rate in this scenario in the 19th and early 20th centuries since the US was much more racist back then and US whites back then would have certainly dreaded the possibility of ever being outnumbered in their country by non-whites. Interestingly enough, there might be less black migration to the Northern and Western US in the 20th century in this scenario since blacks might have to compete with Mexicans for employment in this scenario. Once the US closed its doors to large-scale immigration in the 1920s in real life, black labor was sometimes the only viable labor that was available in some parts of the US. In this scenario, it might be different due to the greater ease of Mexican migration within the US in this scenario as well as due to the much larger number of Mexicans in the US in this scenario. In this scenario, I would certainly expect Mexico to perform better academically than it does in real life--albeit certainly not at the level that White Americans would have performed. Rather, they would have probably performed comparable to the Hispanic American community that exists in the US in real life.

Anyway, what are your own thoughts on this?
 

betgo

Ad Honorem
Jul 2011
6,681
Rather than answer your hypothetical, there were several reasons for not doing that. It was standard in warfare to take the capital and then settle for a few provinces. For example, Prussia did not try to take the whole of France and the French Empire in 1871. It was easier to absorb sparsely populated provinces than the whole country with a different culture and language. The US would need to conquer all of Mexico to absorb it. Mexico would never have agreed to that in a negotiated peace settlement. That might have taken years more. Plus permanent occupation would probably have been needed to maintain control.
 
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Apr 2017
1,737
U.S.A.
At the conclusion of the war the Mexican government had collapsed and it took some months for the American military to find a government to sign the peace treaty. There were great concerns about being bogged down in mexico during this time. Even if America did find some puppets to sign the agreement (which would be seen as illegitimate by the world), they wouldn't have the ability to garrison it. America at the time didn't maintain a large standing army and maintaining a force in southern mexico (where the majority of the population) on garrison duty, fighting against constant rebellions would be unfeasible. America would probably give up and pullout of the south after a couple of years.
As for immigration, it would take decades for there to by much back and forth between southern mexico and the eastern US. There wasn't much infrastructure to connect them and little incentive for one group to move to the other area. If anything this would boost migration to the west as in real life people wanted a fresh start (including Mexican fleeing the constant war of the south).
 
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Zip

Jan 2018
762
San Antonio
The United States would be a Catholic country. Which would be aces with me but I doubt many Americans of the time would have dug the notion.
 
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Frank81

Ad Honorem
Feb 2010
5,180
Canary Islands-Spain
The USA could conquer all of Mexico in 1850, there was no military opposition to that. However, sustaining occupation would be impossible.

The population of Mexico by 1842 was 7,015,509 (Census). Most of this population was concentrated in the centre and the south. This large mass of people couldn't be assimilated into the US, nor kept in peace unless a very tolerant and generous occupation, and integration of the Mexican elites with little or no return to the US. I can't see this practical at all

Another issue would be a much larger occupation than it was. The provinces conquered by the US, roughly 2 million km2 including Texas, were populated by 113,265 people



Source: https://journals.iai.spk-berlin.de/index.php/iberoamericana/article/viewFile/628/312

The states later bordering US were as follow:

Tamaulipas = 100,068
Nuevo León = 101,108
Coahuila = 75,340
Chihuaha = 147,600
Sonora = 124,000
Baja California (detracting Alta) = 9,910

Total = 558,026 of 7,044,140







These data were probably well known to the US "intelligence" of the age, it is clear the US was very cautious on its demands. They took just the bigger territories, with the lesser population, to avoid management troubles. Just Chihuaha was more populated than the entire northern territories annexed by the US

My first hypothesis was that these territories would be a great adquisition for the US. Excepting Baja, now I see how wise the politicians of the US were leaving them off. Sonora, Chihuaha etc of dubious integration, they just served as a buffer zone with the core territory of Mexico, while the US took the "virginal" territories for them.
 
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Futurist

Ad Honoris
May 2014
23,547
SoCal
Rather than answer your hypothetical, there were several reasons for not doing that. It was standard in warfare to take the capital and then settle for a few provinces. For example, Prussia did not try to take the whole of France and the French Empire in 1871. It was easier to absorb sparsely populated provinces than the whole country with a different culture and language. The US would need to conquer all of Mexico to absorb it. Mexico would never have agreed to that in a negotiated peace settlement. That might have taken years more. Plus permanent occupation would probably have been needed to maintain control.
For what it's worth, the user History Learner on alternatehistory.com actually does argue that, at some points in time in 1847 and 1848, having the US conquer and annex all of Mexico was plausible because apparently a coalition of anti-slavery US politicians and uber-expansionist US politicians could both have approved of such a move and thus joined forces to make it happen. I would post a link here but @Naomasa298 said that we are not allowed to post links to rival forums here. Anyway, you can decide on whether History Learner's argument is plausible. Just do a Google search for "History Learner" combined with "All-Mexico".

I do agree with you that it's going to be a much more intense military effort for the US to pacify all of Mexico. I mean, the US did conquer Mexico City, but not the surrounding areas nor the central and southern Mexican countryside. As you said, there would also be a challenge in integrating a relatively large Catholic and non-white population into the US--which is why US politicians such as John C. Calhoun opposed a US conquest of all of Mexico. That said, though, the France analogy doesn't really appear to work here since France probably had more people than Prussia had in 1871 while Mexico had much less people than the US had in 1848.
 

Futurist

Ad Honoris
May 2014
23,547
SoCal
At the conclusion of the war the Mexican government had collapsed and it took some months for the American military to find a government to sign the peace treaty. There were great concerns about being bogged down in mexico during this time. Even if America did find some puppets to sign the agreement (which would be seen as illegitimate by the world), they wouldn't have the ability to garrison it. America at the time didn't maintain a large standing army and maintaining a force in southern mexico (where the majority of the population) on garrison duty, fighting against constant rebellions would be unfeasible. America would probably give up and pullout of the south after a couple of years.
But the US could secure a better border with Mexico in the process, no? :



As for immigration, it would take decades for there to by much back and forth between southern mexico and the eastern US. There wasn't much infrastructure to connect them and little incentive for one group to move to the other area.
Life in the US would be much better than in American Mexico, no?

As for the infrastructure, railroads and whatnot connecting Mexico to the rest of the US could be built in the late 19th century.

If anything this would boost migration to the west as in real life people wanted a fresh start (including Mexican fleeing the constant war of the south).
How much larger do you think that the Western US's population is going to be in the early 20th century in this scenario?
 

Futurist

Ad Honoris
May 2014
23,547
SoCal
The USA could conquer all of Mexico in 1850, there was no military opposition to that. However, sustaining occupation would be impossible.

The population of Mexico by 1842 was 7,015,509 (Census). Most of this population was concentrated in the centre and the south. This large mass of people couldn't be assimilated into the US, nor kept in peace unless a very tolerant and generous occupation, and integration of the Mexican elites with little or no return to the US. I can't see this practical at all

Another issue would be a much larger occupation than it was. The provinces conquered by the US, roughly 2 million km2 including Texas, were populated by 113,265 people



Source: https://journals.iai.spk-berlin.de/index.php/iberoamericana/article/viewFile/628/312

The states later bordering US were as follow:

Tamaulipas = 100,068
Nuevo León = 101,108
Coahuila = 75,340
Chihuaha = 147,600
Sonora = 124,000
Baja California (detracting Alta) = 9,910

Total = 558,026 of 7,044,140







These data were probably well known to the US "intelligence" of the age, it is clear the US was very cautious on its demands. They took just the bigger territories, with the lesser population, to avoid management troubles. Just Chihuaha was more populated than the entire northern territories annexed by the US

My first hypothesis was that these territories would be a great adquisition for the US. Excepting Baja, now I see how wise the politicians of the US were leaving them off. Sonora, Chihuaha etc of dubious integration, they just served as a buffer zone with the core territory of Mexico, while the US took the "virginal" territories for them.
Yes, the US certainly made a very nice and prudent move in limiting its territorial gains to the northernmost parts of Mexico. That said, though, further expanding into Baja California and northern Sonora (specifically into Sonora's northwestern coastline) would have probably been a good idea. I'm well-aware of the 1853 Gadsden Purchase, but this purchase didn't actually include any additional coastline.
 
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Futurist

Ad Honoris
May 2014
23,547
SoCal
The United States would be a Catholic country. Which would be aces with me but I doubt many Americans of the time would have dug the notion.
They might very well not have. Of course, the US did allow unrestricted white Catholic immigration to the US during this time, but a lot of Mexicans weren't actually white.
 

Frank81

Ad Honorem
Feb 2010
5,180
Canary Islands-Spain
Yes, the US certainly made a very nice and prudent move in limiting its territorial gains to the northernmost parts of Mexico. That said, though, further expanding into Baja California and northern Sonora (specifically into Sonora's northwestern coastline) would have probably been a good idea. I'm well-aware of the 1853 Gadsden Purchase, but this purchase didn't actually include any additional coastline.
Yes they could take the risk, Baja and expanding into the Pacific sector probably was possible with the same argument than was annexed the rest of the northern territory: great territory, little population.

In case they risked taking taking more areas of northern Mexico, the US would face a situation they never confronted at all: management of a large alien population.

This was something the European colonial powers were familiar with, the scenario would be something similar to South Africa:

Bantu and Khoi = native Americans
Afrikaners = Spanish-Mexican criollos
British colonists = Anglo-Americans.

There is no equivalent to mestizos in South Africa