When the justices heard oral arguments in Dobbs v. Jackson Women’s Health Organization, the landmark abortion case, one word came up more than any other: viability. The viability line was at the core of Roe v. Wade, and it’s been entrenched in the abortion rights movement ever since. But no one seems to remember how this idea made its way into the abortion debate in the first place. This week on More Perfect, we trace it back to the source and discover how a clerk and a couple of judges turned a fuzzy medical concept into a hard legal line. Voices in the episode include: • George Frampton — former clerk to Justice Harry Blackmun • Judge Jon Newman — Second Circuit Court of Appeals • Khiara Bridges — UC Berkeley School of Law professor • Alex J. Harris — lawyer, former member of the Joshua Generation Learn more: • 1973: Roe v. Wade • 2022: Dobbs v. Jackson Women's Health Organization • Listen to Part 2: If Not Viability, Then What?   Correction: An earlier version of this episode stated that Justice Blackmun was the first to define pregnancy in terms of trimesters. Upon further review, he seems to have been the first to apply that framework to abortion law specifically, but it appeared in at least one medical text earlier, in 1904. We have updated the episode to address this error. Supreme Court archival audio comes from Oyez®, a free law project by Justia and the Legal Information Institute of Cornell Law School. Support for More Perfect is provided in part by The Smart Family Fund. Follow us on Instagram and Facebook @moreperfectpodcast, and Twitter @moreperfect.