As we implicitly acknowledged in Lopez, however, Congress’s authority to enact laws necessary and proper for the regulation of interstate commerce is not limited to laws directed against economic activities that have a substantial effect on interstate commerce. Though the conduct in Lopez was not economic, the Court nevertheless recognized that it could be regulated as “an essential part of a larger regulation of economic activity, in which the regulatory scheme could be undercut unless the intrastate activity were regulated.” 514 U.S., at 561. This statement referred to those cases permitting the regulation of intrastate activities “which in a substantial way interfere with or obstruct the exercise of the granted power.” Wrightwood Dairy Co., 315 U.S., at 119; see also United States v. Darby, 312 U.S. 100, 118—119 (1941); Shreveport Rate Cases, 234 U.S., at 353. As the Court put it in Wrightwood Dairy, where Congress has the authority to enact a regulation of interstate commerce, “it possesses every power needed to make that regulation effective.” 315 U.S., at 118—119.
Although this power “to make … regulation effective” commonly overlaps with the authority to regulate economic activities that substantially affect interstate commerce,2 and may in some cases have been confused with that authority, the two are distinct. The regulation of an intrastate activity may be essential to a comprehensive regulation of interstate commerce even though the intrastate activity does not itself “substantially affect” interstate commerce. Moreover, as the passage from Lopez quoted above suggests, Congress may regulate even noneconomic local activity if that regulation is a necessary part of a more general regulation of interstate commerce. See Lopez, supra, at 561. The relevant question is simply whether the means chosen are “reasonably adapted” to the attainment of a legitimate end under the commerce power. See Darby, supra, at 121.