Can Sovereignties ‘Co-exist’? Indigenous and Crown Authority in Australia

If sovereignty means supreme authority over a given territory, then no territory can have multiple sovereigns. Australian jurisprudence is firm on this point, upholding Crown sovereignty while refusing to recognise Indigenous sovereignties. Collectively organised Indigenous polities, by contrast, do recognise Crown sovereignty. The Uluru Statement from the Heart claims that Indigenous and Crown sovereignty ‘co-exist’. What does this claim mean? On the interpretation I defend, it discloses the incommensurability of Crown sovereignty and Indigenous sovereignties. I argue that Western philosophers can understand Indigenous sovereignty as a form of custodial authority over a given territory. I offer some clarifications about custodial authority and reject an anticipated objection that Indigenous sovereignty so conceived makes decolonisation impossible in any nonmetaphorical sense.