ries are a guide, not a straightjacket. In Cum- mings, we upheld the constitutionality of the Inter- Page 16 national Parental Kidnaping Crime Act ("IPKCA"), 18 U.S.C. § 1204(a). See281 F.3d at 1051. In so holding, we applied the interstate commerce frame- work but noted that Congress has "broader pow