Tell you what. Throw Texas the hell out of the US. Then, run a major public works project WITHIN the US to sever any and all access from Texas to the US. Build a huge wall along the entire border, remove the roadbeds of the interstates and rail lines between Texas and the US, cut off all food and power connections.
Let the Mexican druglords do anything they want to Texas. We won't care, nor even know because the phone and communications systems, including the Internet will also be down.
No food from the upper 49. No meds. No manufactured goods. No guns, no ammo. No nothing.
And, we might as well take a page from Arizona's book and post shoot on sight laws making it open season on illegal Texans when and if they try to get into the US.