In 2006, the Australian parliament introduced new family law legislation about substantively shared overnight parenting arrangements between divorced couples. Other countries and state legislatures are currently debating the merits of similar legislation. A largely unquestionable premise underpins this reform, namely that the majority of children from separated families demonstrably benefit from the ongoing, warm and available involvement of both parents, in a climate of well‐managed interparental conflict. The Australian legislation moves beyond encouragement of shared parenting in divorce cases with adequately functioning parents; it extends into grey areas which, to date, remain poorly serviced by credible research, including its application to children of all ages and to parents experiencing significant levels of ongoing conflict. Drawing on data from a longitudinal high‐conflict divorce sample, this article challenges three assumptions that underpin a legislative preference for shared parenting, that shared parenting is viable and sustainable for divorced parents in conflict, that shared care enables improved cooperation between parents, and that as a result children will be less affected by their parents' conflict. The article further explores the influence of the mediation process on the choice and durability of shared parenting arrangements.