Mexico controlled the territories of California and Texas just as much as Hungary controlled the Romanian lands in 1880.
However California and Texas are today the USA just as much (not Szekelyland) of Transylvania is Romanian
“Mexico controlled the territories of California and Texas just as much as Hungary controlled the Romanian lands in 1880.”
Utter bull$hit. The Mexican military and/or settlers had zero presence in 80% of your fantasy map.
By 1821, Mexico City was strong enough to overthrow the even more decrepit and ineffectual Spanish colonial rule. However, the distant provinces of the current U.S. Southwest were far beyond the reach of the authority of the independent but strife-torn and financially insolvent newborn government in Mexico City. These distant northern provinces received neither military protection nor needed levels of trade from the nascent Mexican government. Under Spanish colonial rule, trade with the USA was forbidden, but at least Spain provided trade and Army protection from hostile Indian attacks. Under Mexican abandonment and neglect, the Southwest received neither trade nor protection from Mexico City.
For example, Comanches and Apaches ran rampant in the 1830s in the power vacuum created by Mexican neglect, burning scores of major ranches that had been active for hundreds of years and massacring their inhabitants. Mexico City could neither defend nor keep the allegiance of its nominal subjects in these regions. Nor did it provide needed levels of trade to sustain the prior Spanish colonial era standard of living. Mexican governmental influence atrophied, withered and died at the same time that American pathfinders were opening up new routes into the region.
Increasingly, a growing United States of America was making inroads into the Southwest, via ships into California, and via wagon trains of trade goods over the Santa Fe Trail from St. Louis. The standard of living of the Spanish inhabitants of California, Arizona, New Mexico and Texas subsequently increased enormously, which is why they did not support Mexico City in the 1846-48 war. In fact, the Spanish-speaking inhabitants of the Southwest never considered themselves “Mexicans” at all, ever. They went, in their own eyes, from Spanish directly to American. To this very day, if you want a punch in the nose, just call a Hispanic native of New Mexico a “Mexican.”
So how long did these self-proclaimed (but newborn), free and independent Mexican governments have even nominal jurisdiction over the American Southwest? For only 25 years, during which time they had no effective control, and the area slipped backwards by every measure until the arrival of the Americans. The Spanish inhabitants of the Southwest never transferred their loyalty from Madrid to Mexico City, because all they received from the chaotic Mexican governments was misrule, neglect, and unchecked Indian raids.
Since then, how long has the area been under firm American control? For over 160 continuous years, during which time the former Spanish inhabitants of the region, (all the while full American citizens), have prospered beyond the wildest dreams of the Mexicans still stuck in Mexico. To compare the infrastructure, roads, schools, hospitals etc. of the two regions is to understand the truth. The Mexican government has been mired in endemic graft, corruption, nepotism and chaos from the very start until today. The ordinary Mexican peons have been trampled and abused, while only the super-rich elites have thrived. This is why millions of Mexicans want to escape from Mexico today, to enjoy the benefits of living in America that they can never hope to obtain in Mexico.