I would like to hear more about the idea that without Santa Anna, we could see more conflict between conservatives and liberals. How did the political spectrum separate out in post-Independence Mexico? By this I mean what broad policies would mark one as either on the left or right of the Mexican political spectrum?
Iturbide's quick abdication always puzzled me. The man set everything up so that he could seize power, turns on the Spanish, makes deals with the rebels, then he gives up power in short order, as soon as the first resistance to his rule appears. I would guess that his overthrow was a blow to the conservatives, but would his continued defense of his regime benefit them? I would think that the longer Iturbide fights for his regime, the more conservatism in Mexico is associated with monarchism (or imperialism I suppose would be a more exact title). If the liberals vs conservatives spectrum was couched in terms of republicanism vs monarchism, then perhaps the Texas Revolt is part of a larger Republican war against the Mexican Empire, and American intervention could be justified as "defending the liberty of the Mexican people" or something. I'm thinking that the United States would try to run Mexico more from the inside, versus the OTL strategy of just slicing off the tasty, unpopulated bits.
But would that Monarchy/Republic debate be that different from the simple Conservative/Liberal of OTL? Maybe I'm wrong, but my understanding was that Texas revolted precisely because there was a dictatorship under Santa Anna, and that revolt wasn't different at first from all the liberal ones that paved central Mexico and the Yucatan at the same time. Yet the Texas case became unique because it actually succeeded, and it happened to have a good deal of American inmigrants. But at first the Texans wanted to be part of Mexico, and they were on the verge of defeat till Santa Anna's almost ASB defeat and capture at San Jacinto.
By the way, there is also another reason to think that an Empire of Mexico surviving would make more difficult Santa Anna's rise. Many Mexican monarchists fled to Cuba after Iturbide's abdication. In 1829 they convinced the Spanish that the Mexicans would receive them with open arms and they launched the Barradas Expedition that landed in Tampico that year. Yet the expedition fell sick of yellow fer as soon as it landed a foot on Mexican soil, and an oportunistic Santa Anna defeated it with a much smaller force. After that he was widely regarded as a hero and he styled himself "Savior of the Motherland".