No, the Commerce Clause is why ALL marijuana is illegal, whether it crosses State lines or not.
Under that understanding of the constitution, the federal government has total control of everything that has a physical presence. That can’t be right.
Exactly. And yet what can’t be, is.
They don't limit their "understanding" to just things that have a physical presence. They claim authority to enact legislation like hate crime laws and the VAWA by saying hate crimes and domestic violence have a "substantial effect on interstate commerce".