The US civil war isn’t what civil wars look like in the modern context. There was a boarder and most of the North was safe. That’s not what modern civil wars look like. They look like Serbia.
You have to go to work and on your way to work there’s someone who’s been sniping people for months. The cops won’t do anything because “let’s go Brandon” or some shit, the mayor no longer has control over the police, and you still have to go to work because you still have to pay for food. So you duck and weave between cars with rotting drivers to get in to your office and you hope you don’t get killed today.
Modern civil wars have no borders. They look like mass shootings, car attacks, snipers, bombings, and other random terrorism. Or they look like the Syrian civil war, with 30 different groups all fighting each other aligning with each other sometimes and fighting others, for decades, sometimes aligned with the government and sometimes against it.
The key thing about Texas is that they have a ton of oil. Even assuming a normal war, the US military lives off oil. If it was quick they could probably do it without dipping in to strategic reserves, but what would happen to the oil infrastructure at the start of the war? Damaging that supply could impact the US ability to wage war, so that’s not a risk they’re going to take.
If anything comes of this beyond Republicans using it to pump up their base, I’ll be surprised.