What does the u. s. government regulate in a mix economy

In theory, ports of entry for goods and people.

Then the alcohol tax

Electricity tax

Long distance tax

Cigarette/tobacco tax

Any Federal Use tax

Then the FDA and the USDA those came about because of a book written by a Sinclair. Stuff like fingers got chopped off when making hamburger and whoups. It went into the hamburger and how filthy the meat packing plants were. Personally, the idea it is interstate commerce doesn't fly. Leave it up to the States. I don't care if the Federal Government gives them what the States need to check. Or better yet. Require the meat packing facilities to have a third party contractor do the inspecting. If the Federal Government did not do it. The price of food might go up a little, but the Federal expenses would decline.