Sibbach v. Wilson & Co.

Sibbach v. Wilson & Co., 312 U.S. 1, was a decision by the United States Supreme Court in which the Court held that under American law important and substantial procedures are not substantive but rather still considered procedural, and therefore federal law applies. Sibbach followed the seminal 1938 case Erie Railroad Co. v. Tompkins, and thus the decision whether to apply the law of the state of jurisdiction or uniform federal rules depended on whether the rule in question was procedural or substantive in nature.