When the National Horsemen's Benevolent and Protective Association first started warning that the Horseracing Integrity and Safety Act would flunk constitutional due diligence as a violation of the private nondelegation doctrine, its arguments were laughed off. The smart set scoffed that the private nondelegation doctrine was dead, a defunct relic of pre-New Deal "Lochner era" jurisprudence. The NHBPA pressed ahead anyway with the simple yet powerful point that in our constitutional system, a private entity cannot wield public powers like making and enforcing law. The Fifth Circuit agreed--twice--and now the...