This is an excellent example of the "tension" between natural law (the theory of law of the DoI and the Constitution) and positive legal theory. The nine black-robed justices of that time were mainly legal positivists. As mentioned earlier, the emphasis of natural law theory is always the human individual; positive law tends to focus on group "equities." (In Roe v. Wade, the contending "groups" involved are mothers as a class, and their unborn children as a class. What doesn't logically add up is the Court asserted the right to privacy as justification for its holding -- but privacy is something applicable only to individuals, not groups; and then it had to be found in a constitutional "penumbra." Needless to say, the entire Roe v. Wade decision is systematically illogical.)
In natural law, respecting the question of abortion, there are only two questions that need to be answered: Is the foetus human? Is it alive? All you need is two "yes" responses to make clear that a preborn alive human has an unalienable right to life and so is deserving of the protection of a just government. This conclusion is lawful according to the dictates of natural law theory, which is derived from JudeoChristian ethics. What the nine black-robed justices did was to turn something "unlawful" -- the termination of a live human -- into something "legal."
But God is not mocked.
You’ve just articulated with facile ease a tension on the legal front I have struggled to articulate for many years. So the tension - which seems to be rearing its ugly head even in the Republican Primary - is between natural law (what we know instinctively to be right) and... positive legal theory. Question: is the latter a synonym for common law? Even common law, expanding out to include many abortion cases rather than three exceptional ones Cyril Means used in SCOTUS testimony in 1973, condemned abortion going back to the 1300s.
And for the first time in our history those black-robed justices narrowed the meaning of what it is to be a person and who it is that is entitled to God-given dignity rather than broadened it.
But God is not mocked.
However you wish to express it, there has been Hell-to-pay ever since.