So that is the future for much of America if this amnesty bill gets through. One big huge socialist barrio. I hope you guys enjoy it!
Neither Starr County nor Cameron County are good examples in reading the Texas Latino vote, especially in South Texas.
Cameron County, which includes Harlingen, has a large population of old-school DINO Germans and therefore makes it more conservative than surrounding areas.
Starr County doesn't have enough population to really warrant comparison to the larger Texas Latino population, but for example Bush 43 in 2004 ran almost 10% ahead of Bush 41 and Ross Perot combined there (Bush 43 in 2004 ran ahead of Reagan in 1984, not many counties in America where you'd find that.)
The best counties for general comparison are Hidalgo County, containing Brownsville and McAllen (Kerry 55%-Bush 45%) and Webb County, containing Laredo (Kerry 57%-Bush 43%). In both counties, Bush 43 ran roughly about 10% ahead of Bush 41 in 1988.
Overall, I would say that the South Texas Latino movement has been about 20% towards Republicans since the mid-1980s and somewhere in the range of 10-15% since the mid-1990s. This is starting from a base range of about 20-25% in the mid-1980s. Now, on the local level, the Republican party still basically does not exist in these areas, but it'll probably just take a strong Hispanic politician from this area at the statewide level to change that, just depends on when this happens (it might be 5 years or 25 years).
Urban movement has been smaller, but is still noticeable. My old CD-29 in Houston is a good example of this.
However, Texas Latinos really do not compare that much to Latinos in other states. Politically, they tend to be socially conservative and fiscally fairly liberal and support free trade, a combination which I don't necessarily believe you'll find anywhere else among Hispanics except southern New Mexico.