"Give what back?"
The only funny part about the extremists in La Raza and certain "Plan of San Diego" advocates claiming Mexican Nationals should "re-take" Texas, New Mexico, Arizona, etc., because it was supposedly "originally theirs" historically they are a little mistaken in their theory Mexicans ever inhabited the area to any extent, before the Norte Americanos colonized it.
The actual history of the region's development, was that Mexico's Government in 1824 thought the sourthwest was nothing but an Indian infested desert wasteland, and wanted the Gringos as a buffer against the Comanches and Apaches. Thus, they opened Texas up for conlonization, but not out of any heatfelt generosity, it was moreover, as protection against the annual spring invasions from the Comanches.
The Comanches and Apaches had inhabited the region above the Rio Grande hundreds of years before the first Spainiard-Mayan cross ever set foot north of the Rio Grande river. And there was good reason.
The Comanches and Apaches had an annoying habit of raiding down deep into Mexico, killing Mexicans, stealing their animals, raping their women, and generally not being very nice to them. So the Mexican Government was more than happy, when Moses Austin offered to bring in a bunch of Gringos to colonize, thus establishing a "Fronteria" (which meant to them at the time, a "Front") in order to be a buffer against Comanches and Apaches raids.
So the problem is, the "Plan of San Diego" advocates say they want to "reclaim" something their ancestors certainly did not want, (and only possessed in theory, since the Indians possessed it at the time) so if it is to be returned to anyone, it wouldhave to be the Comanches and the Apaches, if they wanted any fairness from the "damned big footed creatures of the north".
So until the Comanche Indians start marching and protesting, I believe I'll hang on to my little old piece of ground.