Because environments and people and things conduct their interactions with motives that are multiple, sometimes contradictory, and almost always complex, interactions need to lack clarity in order to capture how it is that the world lacks simplicity.
Instead of underwriting interactions that are simple an authentic social order creates relationships that can carry on the complexity. When the Puritans extol the virtues of plain and simple they are de-emphasizing the material in order to heighten the relational, which is always neither plain nor simple.
The laws of an authentic social order must likewise lack clarity. Authentic social order comes out of the action of the alternating disequilibrium of gift exchange. Authentic social order is the result not of some constitution but of a treaty between a creator and His creatures. Only after the treaty between the creator and His creatures has been abrogated can precise law intervene in an attempt to simulate the treaty through legal, constitutional means.
The more explicit and precise the law becomes the more it bleaches out the complexity of the relationship and the more closely it comes to resemble the mechanical processes of scarcity rather than the biological processes of abundance.