Let's not nominate Kinky Friedman for anything. But here's the part that really matters:
It would be the world's thirteenth largest economy -- bigger than South Korea, Sweden, and Saudi Arabia. But its worth would crater precipitously, after NAFTA rejected it and the United States slapped it with an embargo that would make Cuba look like a free-trade zone. Indeed, Texas would quick become the next North Korea, relying on foreign aid due to its insistence on relying on itself.
On the foreign policy front, a seceded Texas would suffer for deserting the world superpower. Obama wouldn't look kindly on secessionists, and would send in the military to tamp down rebellion. If Texas miraculously managed to hold its borders, Obama would not establish relations with the country -- though he might send a special rapporteur. (We nominate Kinky Friedman.)
In short: the state of Texas would rapidly become direly impoverished, would need to be heavily armed, and would be wracked with existential domestic and foreign policy threats. It would probably make our failed states list in short order. Probably better to pay the damn taxes.Basically.
Of course, it's important to remember that this is just a political stunt and will absolutely not happen. Even Rick Perry ain't that stupid.