1. A computer-implemented method for managing the configuration state of a target entity, comprising: receiving a plurality of policy rules applicable to the target entity, wherein each policy rule includes a constraint expression that references zero or more configuration state variables associated with the target entity and a reference to a configuration state variable may comprise a mutable or non-mutable reference; constructing a model of the policy rules based on at least priority relationships between the policy rules, wherein priority relationships exist between policy rules that include constraint expressions having mutable references to the same configuration state variable; and determining which policy rules are in effect and which are not in effect in an order specified by the model.