Texas v. White was a very biased, pre-determined, uncritical, and superficial decision made by a Republican-controlled Supreme Court at a time when feelings were still very raw over the Civil War. The court simply ignored the mass of evidence that the Union was supposed to be voluntary, that ratification was not mandated as permanent, and that the Constitution does not even describe the Union as perpetual/permanent. The decision also ignored the writings of two of early America's greatest legal giants: William Rawle and George Tucker, both of whom said that secession was an implied and understood constitutional right and that to deny that right would be to reject America's founding principles.
Secession is a lot like divorce. Sometimes the right of divorce is used for invalid/petty/immoral reasons, but no one suggests that we force the couple to stay together, even if one of the spouses opposes the separation.
As unnecessary, foolish, and unjustified as the Deep South's secession was, if the Republicans had not reacted so combatively and had respected the Deep South's right to leave, secession would have been limited to seven states, and those states might well have decided to rejoin the Union once tempers cooled down and Deep South leaders saw that Lincoln was not their enemy.