No answer is possible in the abstract. Virtually all cases present mixed questions of law and fact. Some areas of law, like personal injury cases, are notoriously fact driven, while others, like property law, tend to be rule intensive. Where any particular controversy falls though depends on how the case is configured.
Which means what? That it is impossible to pre-define any limit on the scope of the federal commerce power? Sounds like that "living document" nonsense.