ld that
the States enjoyed a power of "concurrent legislation."

While this formula obviously stems directly from Webster's argument in
Gibbons _v._ Ogden, it covers considerably less ground. Citation,
nevertheless, of the Cooley case throughout the next half century
eliminated the difference and brought the Curtis dictum abreast of
Webster's earlier argument. The doctrine consequently came to be
established, _first_, that Congress's power over interstate commerce is
"exclusive" as to those phases of it which require "uniform regulation";
_second_, that outside this field, as plotted by the Court, the States
enjoyed a "concurrent" power of regulation, subject to Congress's
overriding power.[531]

JUDICIAL FORMULAS

But meantime other formulas had emerged from the judicial smithy,
several of which are brought together into something like a doctrinal
system, in Justice Hughes' comprehensive opinion for the Court in the
Minnesota Rate Cases,[532] decided in 1913. "Direct" regulation of
foreign or interstate commerce by a State is here held to be out of the
question. At the same time, the States have their police and taxing
powers, and may use them as their own views of sound public policy may
dictate even though interstate commerce may be "incidentally" or
"indirectly" regulated, it being understood that such "incidental" or
"indirect" effects are always subject to Congressional disallowance.
"Our system of government," Justice Hughes reflects, "is a practical
adjustment by which the National authority as conferred by the
Constitution is maintained in its fall scope without unnecessary loss of
local efficiency."[533]

In more concrete terms, the varied formulas which characterize this
branch of our Constitutional Law have been devised by the Court from
time to time in an endeavor to effect "a practical adjustment" between
two great interests, the maintenance of freedom of commerce except so
far as Congress may choose to restrain it, and the maintenance in the
States of efficient local governments. Thus, while formulas may serve to
steady and guide its judgment, the Court's real function in this area of
judicial review is essentially that of an arbitral or quasi-legislative
body. So much so is this the case that in 1940 three Justices joined in
an opinion in which they urged that the business of drawing the line
between the immunity of interstate commerce and the taxing power of the
States "should be left to the legi