But in the case of US vs Knight, the Supreme Court ruled that manufacturing is not the same thing as commerce, so the individuals who do not sell their pot are not engaging in commerce that can be regulated.
Now, there may be some later Supreme Court cases saying different things.... Can you think of any? No W’s.
The original intent of the commerce clause would have applied to "commerce" as it was understood at the time. "Commerce" was a separate and distinct entity from both manufacturing and agriculture, and involved only the act of trade, not the articles of trade themselves. Beware of bureaucrats waving dictionaries. They'll screw you every time.
The case dealt with the regulation of monopolies under an Act of Congress. Justice Fuller, writing for a divided court, held that the Act's restraints on commerce did not reach to manufactures. Fuller wrote, "Commerce succeeds to manufacture, and is not a part of it." He provided no authority for his unprecedented contention.
In his dissent, Justice Harlan demonstrated that Fuller's position stood in contradiction to Gibbons v. Ogden. Harlan wrote,
"It is said that manufacture precedes commerce, and is not a part of it. But it is equally true that when manufacture ends, that which has been manufactured becomes a subject of commerce; that buying and selling succeed manufacture, come into existence after the process of manufacture is completed, precede transportation, and are as much commercial intercourse, where articles are bought to be carried from one state to another, as is the manual transportation of such articles after they have been so purchased. The distinction was recognized by this Court in Gibbons v. Ogden, where the principal question was whether commerce included navigation. Both the court and counsel recognized buying and selling or barter as included in commerce. Chief Justice Marshall said that the mind can scarcely conceive a system for regulating commerce, which was "confined to prescribing rules for the conduct of individuals in the actual employment of buying and selling, or of barter."
Marshall's analysis has stood the test of time, Harlan's analysis has stood the test of time, Fuller's has not.
Manufacture precedes buying and selling. Where Congress determines that regulation of the manufacture is necessary to regulate the buying and selling of a given product or service, the regulation necessarily falls with the power of Congress to regulate trade.
In the case of marijuana, the Court noted in Raich that given the fungible nature of the illicit drug that there was no way for Congress to know in advance whether any given manufacture of marijuana would enter interstate commerce, so that regulation of the manufacture was necessary for Congress to control the sale that such manufacture would precede.
I've never seen that point disproved.