Challenging David Holbrook’s ability to use the Administrative Procedure Act to challenge an alleged violation of the Tennessee Valley Authority’s statutory duty to set electricity rates for domestic and rural consumers “at the lowest possible rates,” the TVA and BVU Authority, Holbrook’s local utility, relied on the puzzling APA exception for decisions that are implicitly — not expressly — “committed to agency discretion by law.” The APA provides two exceptions to the general rule that agency decisions are judicially …