So you say, but there's no support for that view in any of the writings of the Founders. It also doesn't square with the language of the Constitution.
Refer to creation of the shoe monopoly and the various other private actions that provided motivations for the Constitutional Convention itself.
I'd be interested in seeing whatever references you have for this. Certainly no mention of this was made in the Federalist. All motivations for the interstate commerce clause that I've read about (and I've read quite a bit) refer to the actions of state governments, not private parties.
Also review the quote from Madison you posted noting that the intent there was to remove State power to favor their own players over those of another State.
That's not what he said. He was talking about states impeding interstate commerce for their own benefits. He wasn't talking about states getting involved in any other way. But regardless, his point was clear that the motivation for the clause was not to give power (over individuals) to the federal government, but to take it from the states.
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"We know of no rule for construing the extent of such powers, other than is given by the language of the instrument which confers them, taken in connexion with the purposes for which they were conferred."
The words are, "Congress shall have power to regulate commerce with foreign nations, and among the several States, and with the Indian tribes."
The subject to be regulated is commerce; and our constitution being, as was aptly said at the bar, one of enumeration, and not of definition, to ascertain the extent of the power, it becomes necessary to settle the meaning of the word. The counsel for the appellee would limit it to traffic, to buying and selling, or the interchange of commodities, and do not admit that it comprehends navigation. This would restrict a general term, applicable to many objects, to one of its significations. Commerce, undoubtedly, is traffic, but it is something more: it is intercourse. It describes the commercial intercourse between nations, and parts of nations, in all its branches, and is regulated by prescribing rules for carrying on that intercourse. The mind can scarcely conceive a system for regulating commerce between nations, which shall exclude all laws concerning navigation, which shall be silent on the admission of the vessels of the one nation into the ports of the other, and be confined to prescribing rules for the conduct of individuals, in the actual employment of buying and selling, or of barter."
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Hence, "The nature of any particular transaction is irrelevant. The nature of the market is what determines applicability."
"He was talking about states impeding interstate commerce for their own benefits."
Means the same as, " the intent there was to remove State power to favor their own players over those of another State."