Holy shit, I just heard of this one.

tl;dr a farmer grew "too much" wheat to feed animals on his own farm according to the government and even though he wasn't selling it SCOTUS said it still somehow constituted "commerce" because reasons.

The Court decided that Filburn's wheat-growing activities reduced the amount of wheat he would buy for animal feed on the open market, which is traded nationally, is thus interstate, and is therefore within the scope of the Commerce Clause.

That one needs a Dobbs reversal.

Wickard v Filburn

Ah yes: you grew this wheat for your own private use, but it's existence impacts the markets because now you won't be buying something that you otherwise might have bought, therefore it's "in or affecting interstate commerce".

A ridiculous argument that, taken to its logical conclusion, grants the federal government unlimited power over everything because every act or failure to act and every piece of property or raw material can potentially affect interstate commerce in some sort of six degrees of separation way.

America as the founders envisioned died in the Civil War, but the 20th century, particularly the New Deal saw the destruction of even the pretense that the nation consists of numerous sovereigns with a federal government that only exists for a few limited purposes and has no powers beyond those granted to it by the Constitution.