"Scuse me?? I live in the heart of Mexas - less than 150 miles from the Mexican border. While I will concede that there are MANY, MANY Hispanics (and, as you point out most are first generation - which I interpret as being those who stayed AFTER Texas independence from Mexico) who have assimilated into American culture, I see massive numbers of Hispanics (and, I'm not categorizing by Mexican, Cuban bankers (?), or three-legged Venezualan anteaters, but I am addressing the general category of Hispanic) who establish cloistered communities within a larger community, who refuse any effort to learn English or assimilate into our culture and try being Americans first BEFORE they try to cram their culture and lifestyle on us.
The Hispanic culture (sez he, again speaking in generalities) has a rich history and much to offer the US. But, by the same token, so does the US.
On a related topic, hasn't south Texas always been predominantly Hispanic, even in the post-annexation period? I understand the big difference is that the Mexican migration shifted to east Texas following WWII.