Most of you probably have no idea who I am. I've been into alternate history for a couple years now and I made an account on this website but I've still mostly just been lurking. I made a couple of god awful maps and realized that wasn't my thing, so I figured I would try my chances at a timeline. This is probably really bad but let me know if any of it is good and if you want to see more...
The Tejas Purchase
Gaining Tejas: Immediately after he gained the white house, President Andrew Jackson sought out to buy the Mexican region of Tejas . In August of 1829, the United States sent an offer of $5 million to the Mexican government exchange for the region of Coahuila y Tejas above the Nueces River. The Mexicans, still recovering economically from their independence war, agreed to the deal. The region of Tejas was officially sold to the United States. President Jackson would appoint Stephen Austin as the first territorial governor for the Tejas Territory.
There were many reasons the Americans wanted to acquire Tejas. The region had a growing American population, which many felt would soon outweigh the ethnic Mexicans in the region. Texans also refused to give up the practice of slavery, which Mexico had first declared banned in 1810. Overall, the purchase would be beneficial for both the United States with her new land, and Mexico with more funds to put towards fixing the country.
Tejas Disputes
Miller Country: The new borders created between the United States of America and the United Mexican States after the Tejas Purchase we very simple. The border followed the Nueces River and then went up two straight lines at a right angle. However, the border of Tejas with the rest of the United States was less clear.
The biggest border unclarity was at a small strip of land by the Red River. Also this territory had technically been given up to New Spain (and thus later Mexico and Tejas) after the Adams-Onis treaty, the territorial government of Arkansas still claimed this small strip of land as Miller County, Arkansas. The Supreme Court decided the dispute should could not continue now that both claimants were part of the United States, and in Pope v. Austin Miller County was officially recognized as part of the Tejas Territory.
Tejas Troubles: The Tejas Purchase was received with great enthusiasm in the south, where it was thought the areas unsuited for slavery in the northern parts of the country would someday be made into free states that would outnumber slave states. Tejas gave new land for a possible slave state to balance out future free states, maybe even two. However, in the northern states, the purchase was seen as an attempt to expand the practice of slavery. Jackson would lose any popularity he had in New England and gain more popularity in the south.