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.)So, Texas would need to court Mexico and Central American nations as a trading partners and protectors. Those very nations would also pose a host of problems for Texas. President Perry might find friends in anti-U.S. nations like Venezuela and Cuba, but their socialist politics would rankle the libertarian nation. And Texas would become a conduit for drugs moving north to the United States from Mexico, maybe even becoming a narco-state. It would need to invest heavily in its own military and policing force to stop drug violence within its borders -- taking away valuable resources from, oh, feeding its people, fending off U.S. border incursions, and improving its standing in the world. 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.
To be fair to Texas, federal taxes are actually a fairly bad deal for them: According to The Tax Foundation's 2005 calculations, the Lone Star State only gets 94 cents in federal spending for every dollar paid in taxes. Update: Chuck Norris stands ready to serve as President of the Republic of Texas. Seriously. Photo used under a CC license from LadyBugBkt.