Militarily speaking, prior to any hypothetical Texan secession, the United States department of defense would withdraw all US military bases and units, manpower and weaponry from the state. The so-called Republic of Texas would be left without a military of any kind, totally defenseless to any other sovereign nation who chose to attack or invade it. Even the paltry Mexican navy could blockade Texan ports and the smallest, weakest Central or South American nation could place and enforce sanctions and embargos on the budding new Republic. The people of Texas would suffer much greater tribulations than they currently do under the federal US government. My best guess is we'd see a mass refugee exodus from Texas the new sovereign nation into surrounding US states. In short, secession would be a living nightmare for Texans.