Law and Custom in the Establishment of Whiteness as Propety

As Harris traces the development and establishment of Whiteness as property she accounts for the influence of both the law and custom. Specifically, she says she is using the feminist legal concept of "positionality" to place each of these in their appropriate historical context, as opposed to merely "remaining within the bipolar confines of custom or [law]"(1727)(See footnote 71).
Harris seems to argue that Whiteness transitioned from an aspect of identity to a property because of the law: "According Whiteness actual legal status converted an aspect of identity into an external object of property" (1725). This would imply that the concept of Whiteness originated outside of the law, and became a privileged position in property through the law.
As Harris recognises later on, the status and origin of property is a contentious matter as property seems to require justification and enforcement, at the very least in order to be effective and allow the owner to profit. Having property in something that I cannot securely enjoy is relatively useless, as I am forced to spend my energy on protecting my property, as opposed to profiting from it. This would then imply that property (specifically the kind of actionable property that serves as the basis for institutionalised wealth disparities accumulated over generations and protected by the state) requires the protection of the law. Whiteness as property really only seems to become potent once the law starts to enforce it, for without the law Whiteness can merely function as a privileged societal status, as opposed to truly serving as property, in the truly potent sense of the word.
In trying to untangle the interrelated effects of custom and law, the concept of positionality becomes critically useful. Given historical context, it seems fair to conclude that custom initially provided the raw materials, which the law then shaped and moulded in order to achieve its desired goal, namely the protection of white property (both of Whiteness itself, and of physical assets in the hands of white people). As Harris concludes: "The law [...] established a pattern -- a custom -- of valorising whiteness." (1728) Custom then served to amplify the law and the effects thereof.