I, too, have given abortion, and the abortion debate, a great deal of thought, of late. I, too, have failed to finish Justice Alito's disingenuous screed.
But, I've been involved in debates on the issue for decades, and have always been of two minds about it. On the one hand, I understand those that see abortion as akin to infanticide - even though they are biologically wrong, and morally simple. On the other hand, as a strong advocate for civil rights (and a card-carrying member of the ACLU), I fully appreciate the importance of the right at issue, and its profound effect on individuals and society.
There is a slippery slope on both sides of the debate, and ideologues like Alito prefer black-and-white answers in a living-color world. Moreover, his answer, unsurprisingly, is entirely wrong, as well as wrong-headed. Down that path madness lies.
Abortion - the deliberate cessation of a pregnancy - has been a fact of life for as long as civilizations have existed. Until very recently, it was not considered a moral issue at all, and a practical necessity for a society. Where it was "outlawed" it was usually for racist or misogynistic reasons - preventing slaves from aborting potential "dividends" or ensuring wives dutifully presented heirs for the benefit of husbands - even at the risk of their own lives. For time immemorial, abortions have been the "safer" option over carrying a pregnancy to term - which is truer today than ever (in the US it is 14 times riskier to carry to term). The motivations for making it illegal have been far from moral (such as undercutting competition).
At this juncture, however, we need to be more pragmatically attuned. It is reliably estimated that 1/4 of all women 15-45 will have an abortion in their lifetimes. Moreover, prohibition only affects the female half of the population directly. Further, the effects of anti-abortion laws fall, as they always have, disproportionately on the most disadvantaged members of society, which creates a greater burden on all of us. Additionally, pregnancy is always a period of uncertainty. At least 20% of pregnancies end in a miscarriage (loss of the fetus before the 20th week of gestation). All of these factors militate toward accepting abortion as an overall public good, which is reflected in polling as well.