Although procedural fairness does not prohibit the combination of the advocacy and adjudicatory functions within a single administrative agency, tasking the same individual with both roles violates the minimum constitutional standards of due process. The irreconcilable conflict between advocating for the agency on one hand, and being an impartial decisionmaker on the other, presents a particular combination of circumstances creating an unacceptable risk of bias.  Accordingly, the DMV violates due process by having its hearing officers in DUI license revocation proceedings serve both as adjudicators and as advocates for the DMV.