"Importantly, public opinion also mirrors the conceptual framework used in the 1973 landmark Roe v. Wade abortion decision. Under that historic ruling, the interests of the mother are paramount in the first trimester, but the state has an interest in protecting the fetus after viability. In the words of the decision: "For the stage subsequent to viability the State, in promoting its interest in the potentiality of human life, may, if it chooses, regulate, and even proscribe, abortion except where necessary, in appropriate medical judgment, for the preservation of the life or health of the mother." The wording of Roe v. Wade aligns almost perfectly with where Americans stand on late-term abortions -- keep them legal to save the life of the mother and in cases of rape and incest, but not for other reasons. Where Americans seem to depart from the decision is in supporting certain restrictions on first-term abortions, particularly those performed because of Down syndrome or solely at the woman's discretion. Roe v. Wade took the power of outlawing abortion out of states' hands, making it legal throughout the country. But its invitation to regulate abortion in ways focused on the health of the mother, as well as to protect the "potentiality of human life" after viability, has enabled states to pass numerous laws limiting how and when abortion can be legally performed. Many of these restrictions are likely consistent with Americans' sensitivities to abortion, but that alignment could change."
January 1, 1970
https://en.wikiquote.org/wiki/Roe_v._Wade