The Mexicans DO want TX (and other US land they claim) back. And they are invading it, just not with their army. The smart thing is the way they are doing it is the have more rights than citizens and citizens have to pay for their welfare.
I watched a four hour youtube on the history of Ukraine. VERY interesting, just made last year or so, and had a few snips of the protestors and others showing the diversity and different views on Russia.
Way back when Russia gained control of Ukraine (300 years ago??) it sought to get rid of the Ukraine language and culture and replace it with Russian. Prior to the communists they allowed them to use their language in books and plays and other things; with a revival in their nationalism to go with it. When the communists took over they got rid of that again, as well as the purges and famines of the Ukrainians, and replacing them with Russians.
So now as we see in Crimea “Hey - these people are pretty much Russians and they should be with Russia!”
Same thing in our Southwest. As that guy says: “Language, culture, borders.” The Russians have that figured out.