Leaving the union: All social security, Medicare, Medicaid disappear immediately.

To be fair if we're talking Texas this part is kindof a moot point and might not be felt.

They're one of like 11 states (don't quote me haha) that rejected free money for Medicaid expansion, so you need to be making like $1,900 a YEAR to be eligible for any kind of aid...unless you're an individual and not a family, in which case, they want you to either suddenly get lots of money or die in a ditch.

Edit - there's a source so I wasn't being intellectually lazy lol. https://www.texasmonthly.com/news-politics/medicaid-expansion-benefits-legislature/

And to add to all the rest of your very good points:

With their power grid, if they actively became hostile we'd just have to wait til the extreme weather crumbles their utilities infrastructure again.