Abstract: Examines criticisms and defenses of the “viability” criterion, which was introduced in Roe v. Wade to mark the cutoff for nontherapeutic abortions. The viability criterion opened a six-month window for “abortion on demand,” which was (and remains) unusual by worldwide standards. Examines the origins of the viability cutoff and shows that it was introduced in later drafts of Blackmun's opinion because it was thought to be more compatible than other proposed cutoffs with the privacy-based reasoning articulated in Roe. The rationale used by the Supreme Court is both mistaken and less relevant given abortion procedures available today. Because the six-month time span for abortion on demand has deepened social divisions on abortion, has generated restrictions that unfairly burden poor and young women, and is not required to give women adequate access to abortion, new criteria for regulating legal abortion need to be developed.

Keywords: abortion, Blackmun, poor women, privacy, Roe v. Wade, Supreme Court, viability,