[tacticalogic]

Here's a link to the document. I believe it's plain enough he'd talking about the Commerce Clause. The last link I gave you explained it a lot more broadly, and it greater detail.

[radicalamericannationalist]

Again, the original document you cite is written forty years after the ratification of the Constitution. The statements of the Founders after that amount of time are of far less reliability than at the time of ratification and the debates because of the political factions that had formed by then. So please cite statements made at the time of adoption of the Constitution.

As to Professor Barnett, it seems he views the original meaning of commerce in terms of trade, not encouraging manufactures.