Justice James Clark McReynolds wrote 75 years ago, in a dissent from a Commerce Clause-impacting labor case, this in part:

We are told that Congress may protect the “stream of commerce….”  Therefore it is said he may be prevented from doing anything which may interfere with its flow.
…
May a mill owner be prohibited from closing his factory or discontinuing his business because so to do would stop the flow of products to and from his plant in interstate commerce?

Apparently he can, when the stream of commerce’s products include government’s ability to spy on its citizen employers.