According to Justice David Souter, it is "most familiar history" that back when the Supreme Court took a restricted view of the commerce power, it also "routinely invalidated state social and economic legislation under an expansive conception of Fourteenth Amendment substantive due process." As the word "routinely" suggests, Souter evidently believed that this Lochner Court struck down a large number of laws on substantive due process grounds' during the years 1897 to 1937.
As discussed later, other observers agree. Although they recognize that the old Court rejected more substantive due process attacks than it accepted, they also suggest that cases of the latter kind numbered approximately 200. This means that during the forty years comprising the Lochner era, the Court used substantive due process to strike down government action an average of about five times a year.
The question of economic substantive due process's impact has intrinsic historical interest. Because the Court seems to be slowly reviving the doctrine, the question is assuming greater practical
importance as well. The prospect of a new economic substantive due process naturally awakens traditional criticisms of the Lochner Court. But some of these criticisms assume that the doctrine had a strong impact.
The first and perhaps the most formidable of these attacks is that because the original meaning of due process was procedural, substantive due process is illegitimate. The usual justification for this positivistic argument is that when courts broadly interpret vague provisions like due process to strike down legislation, they offend democratic values. But the less often economic substantive due process was used in this way, the less vulnerable it is to charges of judicial legislation.
Phillips, Michael J.
"How Many Times Was Lochner-Era Substantive Due Process Effective?,"
Mercer Law Review: Vol. 48
, Article 4.
Available at: https://digitalcommons.law.mercer.edu/jour_mlr/vol48/iss3/4