The decision in Texas v. White is not that much different than the decision in Furman v. Georgia in 1972. The Constitution outlaws cruel and unusual punishment but nowhere does it define what that means. The majority of the court decided that if the sentencing guidlines for imposing capital punishment were not clearly defined and fairly administered then that violated the 8th, as well as the 14th, Amendment. By your definition this constitutes using 'doctrines not expressed or implied by the Constitution'. The court threw out every death penalty sentence across the country. By your definition that no doubt constitutes 'set(ing) up new parameters for guiding Supreme Court decisions'. Undoubtably you would say that was another example of a 'contingent decision' (whatever that means) and that such a decision would be unjust ...'for exactly the same reason that making an ex post facto law is unjust'. And regardless of all that, the verdict held, the sentences were thrown out and life went on. You may not agree with the opinion of the justices that this was an example of cruel and unusual punishment any more that you agree with Chief Justice Chase's opinion that a permenant union formed a more perfect union but it doesn't really matter in either case, does it. Unilateral secession as practiced by the south is not legal and never has been legal, the Supreme Court ruled that it is not.