[jcranmer]

Gibbons v Ogden was about New York's granting of a monopoly on all steamboat services within New York, and the ruling held that "Commerce among the States, cannot stop at the external boundary line of each State, but may be introduced into the interior"--in other words, that the right to regulate interstate commerce necessarily intrudes on the right to regulate intrastrate commerce to some degree.

Wickard v Filburn held that the Commerce Clause extends to regulating the growing of wheat for personal consumption, that involved no commercial transactions whatsoever.