New Texas would have a cartel run puppet government within a year. This is a deeply held belief I have. The oil money ghouls would never give up the ports and refineries. New Texas wouldn't have the strip of land going from Corpus Christi all the way to Port Arthur. It would all get seized by Saudi Arabia or a coalition of interests representing them, and that's including Corpus, Houston, Beaumont, and everything between. Various gulf monarchies already own huge stakes in all that land and oil of current real life Texas. They're not gonna give up some of their biggest ports in North America just because some bumpkins decided they wanted to play at being Stephen F. Austin.

New Texas immediately runs out of money, sells the state to the Sinaloas or Golfos or whoever else tosses money around. International oil committee seizes the southern coastline.