[Mojave]

I asked about two cases. What about in the Sanchez case? Why distinguish a tax from a penalty in that one?

The court said that a tax was valid even when it acted as a penalty designed to inhibit behavior.

It is obvious that § 2590, by imposing a severe burden on transfers to unregistered persons, implements the congressional purpose of restricting traffic in marihuana to accepted industrial and medicinal channels. Hence, the attack here rests on the regulatory character and prohibitive burden of the section, as well as the penal nature of the imposition. But, despite the regulatory effect and the close resemblance to a penalty, it does not follow that the levy is invalid.

[publiusF27]

They said it "closely resembled" a penalty, but that seems to suggest it was NOT one.

defendants attacked the constitutionality of this subsection on the ground that it levied a penalty, not a tax.

...

The tax in question is a legitimate exercise of the taxing power despite its collateral regulatory purpose and effect.

Why would they want to make that distinction? The answer is given clearly in Sonzinsky:

The case is not one where the statute contains regulatory provisions related to a purported tax in such a way as has enabled this Court to say in other cases that the latter is a penalty resorted to as a means of enforcing the regulations. (citing 3 cases)