What you believe matters not, as illegals can't serve in the UNITED STATES (there's 50 of those, in case you haven't heard) plus other commonwealth and territories) Military.
There have been illegals in Tehas back when it was part of Mehico and illegales came in from el Norte. Lots.
In recent years, due to oil, Texas is no longer a net recipient of Federal aid.
Should that change, it's back to normal and the only thing it might one day be cleaving from is itself since a big chunk of arid scrubland is an expensive creature to sustain and jealousy over who gets a bigger slice of the dole is an ornery beast.