The U.S. Constitution bars a group of current and former Cook County Probation Department employees from suing Chief Circuit Judge Timothy C. Evans for allegedly failing to exercise his authority when they received allegedly discriminatory treatment, a federal judge ruled.The plaintiffs, all of whom are black, brought the claim under the Illinois Probation and Probation Officers Act. They allege Evans abandoned his statutory duty to ensure the allegedly discriminatory treatment they received did not violate state or …