I might just as easily say that I can't imagine how they found such a prohibition of unilateral secession in that document. But what I'm asking of you is to assume to begin with that there is a plausible construction of the Constitution that could support unilateral secession, and then ask yourself if the court could realistically be expected to apply that construction at that particular point in our history. If you can't, then it makes no sense for you to say that Texas vs. White settled anything, because the court had to rule the way it did. They knew what the conclusion had to be from the beginning of the case, and then set themselves upon the task of validating it however they could. But the only way a ruling on anything can be convincing is if it's uncoerced.
And the abortion controversy doesn't even begin to compare whith what the Chase court was facing.