Some good questions about Carolene Products:
QUESTION: The Filled Milk Act was an act of Congress that I presume was enacted pursuant to the Commerce Clause. Forgoing the first two basis for interstate regulation we'll assume that interstate commerce of the product ("Milnut") has a substantial relation to interstate commerce and the basis for the action by Congress falls within its powers. What is unclear, but I presume, is that Carolene Products challenged the statute because the act amounted to a deprivation of its property.
ANSWER: I think that is essentially correct. More specifically, it might have phrased the claim as the law infringing on its fundamental right to contract -- to sell its product (which it believed was perfectly safe) to willing buyers. This is the potential contract that was forbidden.
QUESTION: Since the action is Congress' then the 5th Amendment is the proper recourse to challenge the deprivation. Is it correct to understand that Carolene Products is asserting the right at issue (the right to manufacture and ship "Milnut") is a "substantive due process right" or an "economic liberty." I am at a loss to define what either term really means.
ANSWER: Essentially, yes. It was a substantive right to economic liberty which the Court had previously recognized as a fundamental right under the Due Process Clause (in both the Fifth and Fourteenth Amendments). I'm not sure we can get too far into the exact contours of that right, as it would require delving into hundreds of cases decided between 1880 and 1937. But the basic idea was that, absent a "legitimate public concern" -- a clear health, safety, or morals interest -- the government was prohibited from interfering with willing buyers and sellers in the economic marketplace. Hence, no minimum wage, maximum hour, pro-union legislation or the like. Carolene Products likely would have prevailed on its claim during the Lochner era because the safety rationale for the legislation looked pretty weak, and the Filled Milk Act likely was meant to protect regular milk producers from competition.
QUESTION: We've seen examples of economic rights tied to minimum wage standards (West Coast Hotel) maximum work weeks (Lochner), prohibition on the manufacture or sales of a product (Carolene) and prohibitions for the sales of services without a prescription (Lee Optical). Are challenges to economic regulation which impedes my freedom to freely engage in activities for compensation (beyond the freedom to contract) necessarily challenges to substantive due process rights because they are a deprivation of property or "economic liberty"?
ANSWER: Not if the claim is that the regulation in question violates another clause, such as the Contracts Clause or the Takings Clause. But as to the cases you mention, yes, because they are substantive rights (that is, they are unrelated to the procedure by which property is being taken) that the plaintiff claims are protected by the Due Process Clause.
QUESTION: This appears to me to make the most sense. And so long as the Court construes that Congress, or a State legislature, had a rational basis (the government had a legitimate purpose and the legislation was reasonably related to that purpose) then economic regulation, which might have the affect of depriving me of income or property does NOT itself violate my substantive due process.
ANSWER: I would agree. Unless, apparently, we are talking about punitive damages. There, the Court seems to be applying something more than rational basis review.