From the abstract for Ilan Wurman, The Origins of Substantive Due Process, University of Chicago Law Review, Forthcoming:
In the antebellum nineteenth century, courts often voided legislative acts for substantive unreasonableness or for exceeding the scope of legitimate police powers. Contrary to the assertions of a number of modern scholars, however, this tradition does not support the concept of economic substantive due process. Courts voided municipal acts exceeding the scope of legitimate police powers on two grounds — the law of delegation and the law of municipal corporations — that did not apply to acts of state legislatures. The states themselves were limited to reasonable exercises of the police power only when their asserted authority came into potential collision with federal constitutional requirements, namely the commerce and contracts clauses.
It was only late in the century, after the adoption of the Fourteenth Amendment, that a police-power version of substantive due process emerged as a limitation on state legislatures as courts began conflating, under the guise of “due process of law,” earlier doctrines that had used a similar vocabulary but for distinct purposes. Police-power limitations on state legislatures regulating purely internal matters therefore probably cannot be justified by any antebellum legal conception of due process of law. It is possible, however, that such limitations could find support in the privileges or immunities clause by analogy to antebellum commerce clause and contracts clause jurisprudence.