Can Congress ban an item from being sold within a single state?

[Emsworth]

Congress' power to regulate commerce among the states has, undoubtedly, been abused more than any other (followed closely by the power to spend for the general welfare). The federal government has, claiming the authority granted by this clause, presumed to regulate several matters that ought to be within the sphere of the states alone. Even that proponent of a large federal government, John Marshall, would scoff at the interpretations of the modern judiciary.

In Gibbons v. Ogden, Chief Justice Marshall wrote, "Comprehensive as the word 'among' is, it may very properly be restricted to that commerce which concerns more States than one." Undoubtedly, the word "among" implies that multiple states must be involved in the commerce in question. Marshall also wrote, "It is not intended to say that these words comprehend that commerce, which is completely internal, which is carried on between man and man in a State, or between different parts of the same State, and which does not extend to or affect other States."

The Supreme Court has, in more recent times (especially since the 1930s), taken a very different approach. It has held that anything that even affects the "current of commerce," including the most minor transactions between persons in the same state, may be regulated by Congress. This is a dangerous interpretation that unduly expands federal authority. The Constitution only authorizes the regulation of "commerce ... among the states," not "anything that affects commerce among the states." The courts have given the words "among the states" almost no effect at all.

Marshall's view (considered too broad by some jurists of the era) is perfectly correct: Congress may not regulate the sale of a good within a single state, even if such a sale somehow "affects" interstate commerce.

[Emsworth]

No. I mean within each of the individual states.

What if a company produced iron ore in Minnesota and sold it in Duluth to a transportation company; and then the transportation company transported it to Pittsburgh, where it was sold to a steel mill; and similarly coal was mined in West Virginia, sold to a transportation company which brought it to Pittsburgh and resold the coal to the steel company.  The steel company used the iron ore and coal to produce steel, which it sold to another transportation company which took the steel to Detroit and sold to an auto company, which produced a car which it sold to a transportation company, which took the car to Florida and sold it to a dealer, who cold it to a rental company who drove it Augusta, Georgia where it was leased to a pizza delivery service that sometimes delivered into South Carolina.

Any interstate commerce?

In each of those cases, it is not the sale but the transportation that constitutes interstate commerce.