Jonathan had a post on Friday about the Fifth Circuit's new case, National Horsemen's Benevolent & Protective Ass'n v. Black. It has a few fun features: (1) it's one of the rare cases to strike down a federal statute based on the non-delegation doctrine, and (2) it's one of the even rarer cases to do based on a supposed theory that delegations to private parties are judged by a stricter standard—or are even per se unconstitutional.
In this case, the statute is the Horseracing Integrity and Safety Act, and the private entity is the Horseracing Integrity and Safety Authority. (The case calls the statute HISA and the entity the Authority, so I'll follow the same convention.) The Authority is supposedly subject to the FTC, but the Fifth Circuit finds that the extent of FTC oversight is not nearly great enough, so the Authority wields a lot of coercive power all by itself, which makes this an unconstitutional private delegation.
Now I think the supposed "private nondelegation doctrine", which the Fifth Circuit calls a "commonsense principle", actually doesn't exist. Not just that it's a bad idea: actually, no Supreme Court case [UPDATE: holding] gives it any support, and several Supreme Court cases cut the other way and uphold private delegations under the nondelegation doctrine. (The D.C. Circuit's first Amtrak opinion does give it support, but that opinion was vacated by the Supreme Court.) Plus, such a doctrine would also be a bad idea. (My broader thesis is that there are a bunch of different doctrines that could be called "nondelegation doctrines", but here we're only talking about the Article I Nondelegation Doctrine, so for now I'll stick to that. But I'm working on an article on the broader issue, which I'll probably post here eventually.)