n in keeping intercourse between the States
untrammeled by local selfishness; and in 1851 the Court, heeding the
spirit of compromise of the day, decisively accepted for the most
important category of cases Marshall's principle of the exclusive
control of interstate and foreign commerce by Congress. *

* Cooley vs. the Board of Wardens, 12 Howard, 299.

Still, until the eve of the Civil War, the theory of the Constitution
held by the great body of the people, North as well as South, was that
it was a compact of States. Then in December, 1860, South Carolina
announced her secession from the Union. Buchanan's message of the same
month performed the twofold service of refuting secession on State
Rights principles and of demonstrating, albeit unwittingly, how
impossible it was practically to combat the movement on the same
principles. Lincoln brought the North back to Marshall's position when
he remarked in his Inaugural Address: "Continue to execute all the
express provisions of our National Constitution, and the Union will
endure forever."

The Civil War has been characterized as "an appeal from the judgments of
Marshall to the arbitrament of war." Its outcome restored the concept of
the National Government as a territorial sovereign, present within the
States by the superior mandate of the American People, and entitled to
"execute on every foot of American soil the powers and functions
that belong to it." * These powers and functions are, moreover, today
undergoing constant enlargement. No one now doubts that in any clash
between national and state power it is national power which is entitled
to be defined first, and few persons question that it ought to be
defined in the light of Marshall's principle, that a Constitution
designed for ages to come must be "adapted to the various crises of
human affairs."

* Justice Bradley in ex parte Siebold, 100 U.S., 371.

It is only when we turn to that branch of Constitutional Law which
defines governmental power in relation to private rights that we
lose touch with Marshall's principles. As we have seen, he dealt in
absolutes: either power was given to an unlimited extent or it was
withheld altogether. Today, however, the dominant rule in this field of
Constitutional Law is the "rule of reason." In the last analysis, there
are few private rights which are not subordinate to the general welfare;
but, on the other hand, legislation which affects private rights must
ha