[Savage Beast]

"Texas v. White (1869), U.S. Supreme Court case in which it was held that the United States is “an indestructible union” from which no state can secede."

Other Supreme Court decisions have been reversed, e.g. Dred Scott, Brown v Board of Education, et al.

[Nero Germanicus]

Dred Scott wasn’t overturned. It was rendered moot by the passage of the 14th Amendment. Brown v Board is still the law of the land but you are correct that any Supreme Court decision can be reversed. Its just that Texas v White has not been reversed over the last 148 years.