The True Nature of the Mexican American War

If the Mexican American War (and the Texas Revolution) was not a war pitting Mexico versus the United States (or Anglos and Mexicans), then what was it?

The Mexican War was sparked by Texas's fight for freedom from Mexico and the United States' acquisition of the state. The United States and Mexico engaged in a war from 1846 to 1848 to seize territories that stretched from Texas to the Pacific Ocean. The Texas Revolution, also known as the War of Texas Independence, was a conflict between Mexico and Texas colonists that lasted from October 1835 to April 1836 and led to Texas's independence from Mexico and the establishment of the Republic of Texas. Although the Battles of Gonzales and San Jacinto served as the beginning and end of the Texas Revolution, political unrest and armed warfare pitting Texans and Tejanos against the Mexican government's armies had been ongoing at least since 1826.

If the Mexican American War was not a conflict between Mexico and the United States, what was it about?

The Mexican American War was primarily about Texas fighting for its independence from Mexico and the United States taking advantage of the situation to acquire more territories in the region.