1. A system to define and enforce policies on an Open Mobile Alliance Device Management (OMA DM) enabled mobile client device coupled to a server computer over a computer network, comprising: a mobile client device comprising a processor and a non-transitory memory; a server-side process configured to allow creation, modification and transmission of defined policies including decision policies and active policies to the mobile client device, wherein the decision policies control access to mobile client device resources using one or more of a role of a user requesting access and a circumstance of the request, wherein the active policies associate one or more operations of the client device with an occurrence; and a client-side process executed on the mobile client device and configured to store the defined policies in an OMA DM management tree in the memory of the mobile client device as management objects, wherein each policy of the defined policies is represented as a subnode of the management tree, wherein a policy conflict module determines a set of the defined policies relating to at least one of the occurrence and the one or more of a role of a user and a circumstance of the request, identifies conflicts between defined polices of the set before application of any defined policy of the set, and resolves the conflicts using a priority.