s power
extended to the carriage of passengers as well as of goods and to
vessels propelled by steam as well as to those driven by wind. "The one
element," said he, "may be as legitimately used as the other for every
commercial purpose authorized by the laws of the Union."

Two years later, in the case of Brown vs. Maryland, * Marshall laid down
his famous doctrine that so long as goods introduced into a State in the
course of foreign trade remain in the hands of the importer and in the
original package, they are not subject to taxation by the State. This
doctrine is interesting for two reasons. In the first place, it implies
the further principle that an attempt by a State to tax interstate or
foreign commerce is tantamount to an attempt to regulate such commerce,
and is consequently void. In other words, the principle of the
exclusiveness of Congress's power to regulate commerce among the States
and with foreign nations, which is advanced by way of dictum in Gibbons
vs. Ogden, becomes in Brown vs. Maryland a ground of decision. It is a
principle which has proved of the utmost importance in keeping the field
of national power clear of encumbering state legislation against the day
when Congress should elect to step in and assume effective control. Nor
can there be much doubt that the result was intended by the framers of
the Constitution.

* 12 Wheaton, 419.

In the second place, however, from another point of view this "original
package doctrine" is only an extension of the immunity from state
taxation established in M'Culloch vs. Maryland for instrumentalities of
the National Government. It thus reflects the principle implied by that
decision: where power exists to any degree or for any purpose, it exists
to every degree and for every purpose; or, to quote Marshall's own words
in Brown vs. Maryland, "questions of power do not depend upon the degree
to which it may be exercised; if it may be exercised at all, it may
be exercised at the will of those in whose hands it is placed."
The attitude of the Court nowadays, when it has to deal with state
legislation, is very different. It takes the position that abuse of
power, in relation to private rights or to commerce, is excess of power
and hence demands to be shown the substantial effect of legislation, not
its mere formal justification. * In short, its inquiry is into facts. On
the other hand, when dealing with congressional legislation, the Court
has hitherto alw