Both Roe and Casey were dependent upon the claim that abortion is part of a right to “privacy” within the substantive due process protections of the 14th Amendment. But neither case relied upon a recognizable or legitimate due process test.
Pre-Roe, the court required such rights of due process to be “established beyond debate as an enduring American tradition” and “implicit in the concept of ordered liberty.”
Post-Roe, the court reiterated these pre-Roe standards and additionally stated that substantive due process rights must reflect a “careful ‘respect for the teachings of history [and] solid recognition of the basic values that underlie our society.’”
Roe v Wade was 7-2 opinion authored by Justice Blackmun that barred states from regulating abortion in the first trimester, allowed for some regulation in the second, and permitted total bans in the third.
However, there are elements of the ruling that are rarely discussed, possibly on purpose.
Blackmun’s ruling included a few elements that gave precedent to Alito’s striking of the decision.
The Right to Privacy regarding abortion is not only not Absolute, but it all hinges upon proving the personhood of the unborn. At the time, science had not progressed to a point experts would weigh in on such an idea of the personhood of the unborn. However, has that been proven, according to Blackmun’s opinion, the woman seeking an abortion would “no longer be alone in her personhood.”
In his original opinion on Roe, Blackmun says, “If the suggestion of personhood is established, the appellant’s case, of course, collapses.”
Blackmun gave room for the evolution of scientific concepts regarding gestation and fetal development. In the original opinion, Blackmun wrote, “when those trained in the respective disciplines of medicine, philosophy, and theology, are unable to arrive at any consensus, the judiciary, at this point  in the development of man’s knowledge, is not in a position to speculate to the answer [as to when life begins]. Today’s leaps and bounds in medical science today would suggest they can.”
Planned Parenthood v. Casey replaced Roe’s standard of review with an undue burden standard. Four justices dissented at this time, saying Roe should be struck down.
Under the Casey ruling, the Court determined viability in the second and third trimesters and the absence of a woman’s personhood at a reasonable point.
Casey was a plurality ruling as well, and in the second ruling in the case, abortion in the first trimester was regulated. Under Casey, states could far more easily regulate abortions at any time during a pregnancy.
Under Casey, any abortion regulation would now be presumed constitutional unless someone could prove that it imposed undue and significant burdens on a woman’s ability to access an abortion.
Since that 1989 Casey ruling, the groundwork has been laid for this week’s historic decision to overturn Roe and return the full framework of abortion legislation to the state level.
These factors have rarely been discussed at length by the majority. Doing so would not have supported the rhetoric of pro-abortion rights and the desire to control the outcome at the federal level.
Many states have already moved to ban abortions. Many laws will ban virtually all abortions, except to save the life of the mother or in cases involving rape. A dozen states have legislation known as “trigger laws” because they were drafted to go into effect if Roe and Casey were overturned. An analysis by the Guttmacher Institute predicts that 26 states are likely to ban all or nearly all abortions.