"Mississippi targets viability as the key constitutional concept. While often placed at approximately 24 weeks, viability is an inherently subjective standard and depends on many variables. Medical advances have now made the survival of even 22-week-old unborn children possible. Nearly four decades ago, in Akron, Justice Sandra Day O’Connor observed: “As medical science becomes better able to provide for the separate existence of the fetus, the point of viability is moved further back toward conception.” Viability is no more an objective standard today than it was then. With O’Connor’s support, the Supreme Court in Casey appeared to simplify its method of evaluating abortion restrictions by abandoning Roe’s system of different rules for different trimesters in favor of a two-part framework. Mississippi points out, however, that all the Court succeeded in doing was creating another subjective, unworkable standard of whether a restriction is an “undue burden” on the right to abortion. Mississippi argues that there “is no objective way to decide whether a burden is ‘undue,’” and in case after case, the court has been deeply divided “not just over what result Casey requires...but also over what Casey even means.” Mississippi’s brief also addresses Roe’s real foundation, namely, the “detriment” that prohibiting abortion would impose on women. The circumstances that pregnant women face have changed markedly in the past 50 years. These include expansion of the type and flexibility of work opportunities, laws preventing pregnancy discrimination, provision of sick and family leave time, access to childcare and affordable contraception, and “safe-haven” laws. Women today are, more than ever before, able to avoid the “detriment” that the Supreme Court described in 1973 as practically inevitable. Women have, Mississippi reminds the Court, reached “the highest echelons of economic and social life independent of the right bestowed on them by seven men in Roe.”"