There's an article in The NY Times related to what John has written, "In Texas, an Emerging Problem for Democrats on the Border".
https://www.nytimes.com/2020/11/07/us/texas-democrats-red-blue.html

Here's an excerpt:

Many residents in this part of Texas have strong Christian, anti-abortion, pro-gun and back-the-blue views that put them more in line with conservatives than liberals, and in Zapata, there is a strong sense among his supporters that Mr. Trump will bring jobs to the economically struggling region.

In a brief exchange during the final presidential debate, Mr. Biden had said he would “transition from the oil industry” because of its pollution, a remark that did not go unnoticed by Zapata residents, including Yvette Gutierrez De Leon, 56, who is a secretary for an oil-field services company and who voted for Mr. Trump.

“At the end of the day, in the little bit of oil field that is still left, if it goes away tomorrow our county will go away,” Ms. De Leon said. “Oil is all we have here."