I am an amateur historian with only a couple days' research under my belt, but I am putting together a theory that paints the Mexican-American War as a war of purely American aggression (Texas as the Crimea of the U.S.). Perhaps this theory has already been accepted by historians?
Did any relevant Mexican authority ever acknowledge the secession of Texas before the start of the Mexican-American War?
Small clashes arose between the two countries for several years afterward. The war between Texas and Mexico did not truly come to an end until the Mexican-American War of 1846.
A theory that paints the Mexican-American War as a war of purely American aggression (Texas as the Crimea of the U.S.). Perhaps this theory has already been accepted by historians?
Yes, of course this is the accepted theory among the Soviet/Russian historians. It has, of course, nothing to do with reality.
Texas was de facto independent for 10 years(!) until the Mexican-American War. Russian troops entered the Ukrainian province of Crimea in the spring of 2014, then rigged a "referendum".
Russia guaranteed the Ukrainian borders in 1994, then violated its own guarantees 20 years later. The borders between Mexico and the US in the early 19th century were much more nebulous: they were the outcome of the Seven Years' War and defined borders between France and Spain.
Texas was empty of both Mexicans and Americans early in the 19th century (there were Amerindians there, but they "do not count" for the purposes of this question). Americans colonized it faster than the Mexicans did, then seceded. The population of Crimea has been relatively stable for many decades (after the Stalin's deportations), and has been a recognized part of Ukraine for half a century.
If anything, if Crimea is Texas, then Russia is Mexico.
It's common knowledge in Texas (we study our state history) that General Santa Anna acknowledged Texas' independence after his defeat at the Battle of San Jacinto.
I suppose it depends on whether you count General Santa Anna as a relevant official.
"In exchange for his freedom, Santa Anna recognized Texas’s independence; although the treaty was later abrogated and tensions built up along the Texas-Mexico border." History.com