Considering how the Texas Revolution worked out,
What if the Texas revolution had resulted in the US getting more directly involved, sparking a war with Mexico. Who'd win in this scenario? Would the US, led likely by Andrew Jackson at this point in time, achieve the total humiliation of Mexico as Polk did OTL? Or can the Aztec nation at least be able to fight back, even if just enough to not lose much territory? PS: Totally not inspired by Vicky 2!
Considering how the Texas Revolution worked out, seems adding the US into the mix means the territories that ended up in the Cession are going to be taken as well.
During the Texas war (October 2, 1835 – April 21, 1836, presumably the time frame of the POD) the US had 12.9 million people (~2 million enslaved), which is roughly 4 million less than in 1840 ... the population of Mexico is unknown, but as late as 1900, it was only about 13 million, so presumably it may be in the 4-6 million range in the 1830s; the economic, organizational, and political stability advantages are all in the US favor as well, of course. Western expansion does re-open the issue of the expansion of slavery, but given the general shared interest in securing the continent, that - presumably - can be dealt with in terms of domestic politics, as it was historically.
US president is Andrew Jackson; secretary of war is Lewis Cass; secretary of the navy is Levi Woodbury; commanding general is Alexander Macomb, and the two senior BGs are Scott and Edmund Gaines. USMA opened in 1802, with Sylvanus Thayer as supe from 1817 to 1833, so 21 classes had graduated by 1832. The US had, of course, engaged in campaigns against peer competitors (British in 1812-15) and irregulars (those on the old northwestern and old southwestern frontiers) as well as overseas (in North Africa, for example); the Mediterranean Squadron was formed as early as 1801, and the Pacific Squadron in 1821.
Mexico is led by Santa Anna.
One would expect the US might avoid the equivalent of Scott's expedition to Central Mexico in an 1830s war; instead, the focus would be on Texas, New Mexico, and California, and such a war would certainly would be within the capabilities of the US in the 1830s.
Best,