How did the growth of the united states threathen spains hold on texas?

Spain had claimed ownership of the territory in 1519, which comprised part of the present-day U.S. state of Texas, including the land north of the Medina and Nueces Rivers, but did not attempt to colonize the area until after locating evidence of the failed French colony of Fort Saint Louis in 1689. In 1690 Alonso de León escorted several Catholic missionaries to east Texas, where they established the first mission in Texas. When native tribes resisted the Spanish invasion of their homeland, the missionaries returned to Mexico, abandoning Texas for the next two decades.

Explanation:

since most of current immigration into the u.s., both legal and illegal, is coming from latin america. it would be very difficult to imagine or rationalize a country my fellow citizens are trying desperately to flee into, would pose a threat to my prosperity or freedom. since the u.s. has a long history of intervention, but no record of permanent occupation, i would not feel oppression is the main objective.  

the largest free trade nation, along with the largest gdp in the world wanting to expand it's economic policy on us, and including us, could only be positive. the u.s. government has no interest in, or way of simply forcing american culture on us. and has no track record of it. other nations that adopted american social culture, or "americanization" did so voluntarily, mainly through the choice of allowing american businesses and u.s. citizens to come into their nations, as free operatives.

study of past cultures