Sanctuary cities are also illegal under federal law, but no one is doing anything about it. Do you want to leave it up to the states as well?
prohibits states from providing a postsecondary education benefit to an alien not lawfully present in the United States on the basis of residence unless any U.S. citizen or national is eligible for the same benefit.
All US citizens are eligible for in-state tuition in TX if they have lived in the state for 3 years. In fact, US citizens only have to have lived there for 1 year.