Modern doctrine distinguishes channels of interstate commerce, instrumentalities and persons or things in commerce, and intrastate economic activity with a substantial relation to interstate commerce. Aggregation can matter for economic conduct. A noneconomic local activity requires a more careful constitutional connection than a commercial transaction crossing state lines.

The clause can support national regulation of private conduct and can preempt conflicting state rules. It does not ordinarily authorize Congress to order a state legislature or executive to administer the federal program. That separate anti-commandeering limit concerns the form of federal action, not whether commerce is affected.

Do not answer every economically consequential scenario with the Commerce Clause. Identify what Congress regulates, whether the activity is commercial or interstate, and whether the statute contains a jurisdictional connection. States retain broad police powers even though valid federal commerce regulation prevails when the two laws conflict.

Video lesson: Federalism: Crash Course Government and Politics #4