[Aurelius]

"In Texas v. White it was not a prospective decision."

And what is your basis for that statement?

"I'm not sure that I am following this 'contingent' decision stuff."

By "contingent decision" I mean a decision like Texas v. White (or Roe v Wade) which was not logically necessitated by the Constitution and existing law but reflects the personal attitudes and philosophy of the Justices sitting at the time, as well as possibly other contingent effects (such as current public opinion), making it impossible to have been anticipated, even in principle.

[Non-Sequitur]

Because prospective decisions are clearly identified as such in the opinion. Since the majority opinion in Texas v. White clearly states that the Texas ordinance of secession was without basis in law and therefore null, then it is clearly not a prospective decision.