Procedure, Substance, and Erie.

The article focuses on the proposition of a principle explaining the results of the Enabling Act and procedural Erie cases in the U.S. Supreme Court. It avoids the efficiency-based or rights-based arguments with discussions on procedure. It investigates the tests used in identifying when the federal courts should apply a state-based rule. It also assumes that the Act and the Erie cases are good as they reflect the proper rulemaking authority allocation between the state and the federal systems.