That might be a good movie plot, but it's not reality. Texas trying to secede would an enormous act of sedition that would warrant any and all means to put down.

The United States isn't going to just sit back and allow Texas to become its own country because of concern for the optics of enforcement. It would be grounds for civil war, and the death and destruction that would follow would be unprecedented.

It's easy to sit back and imagine scenarios in which these secession fantasies would be successful, but it truly is utter nonsense.