Photographer: David Paul Morris/Bloomberg A federal judge set ground rules for a dozen states to pursue a legal challenge to the Justice Department’s approval of Hewlett Packard Enterprise’s $14 billion acquisition of Juniper Networks amid allegations the deal was politically tainted. The order issued Wednesday sets the stage for a Colorado-led group of state attorneys general to investigate what led federal antitrust enforcers to reach a settlement with the companies that allows the merger to proceed. ...