The Telecommunications Act sought to foster a competitive market in telecommunications. To enable new firms to enter the field despite the advantages of the incumbent local exchange carriers ('ILECs'), D got broad powers to require incumbent local exchange carriers (ILEC)to make 'network elements' available to other telecommunications carriers. Congress left D the choice of elements to be 'unbundled,' specifying that in doing so it was to consider, at a minimum, whether … the failure to provide access to such network elements would impair the ability of the telecommunications carrier seeking access to provide the services that it seeks to offer. Courts have faulted D's efforts to identify the elements to be unbundled. D has now tried a different approach in the application of § 251(d)(2). D delegated to state regulatory commission’s authority to determine if CLECs (competitive local exchange carriers) were impaired by any unbundling issues in specific areas of their jurisdictions. D directed the state commissions to eliminate unbundling if a market contained at least three competitors in addition to the ILEC, or at least two non-ILEC third parties that offered access to their own switches on a wholesale basis. D gave the states virtually unlimited discretion over the definition of the relevant market. If the triggers were not met, D instructed the states to consider whether, despite the many economic and operational entry barriers deemed relevant by D, competitive supply of mass-market switching was nevertheless feasible. If a state failed to perform the requisite analysis within nine months, D would step into the position of the state commission and do the analysis itself. Any party 'aggrieved' by a state commission decision could seek a declaratory ruling from D, though with no assurance when, or even whether, D might respond. Ps petitioned the Court of Appeals on the basis that D’s delegation to the state commissions was ultra vires.