thirdly, the delegation in many instances of like powers to so-called
independent agencies or commissions, in which are merged in greater or
less measure the three powers of government of Montesquieu's postulate.
Under Roosevelt the first two of these developments were brought to a
pitch not formerly approximated, except temporarily during World War I.

The truth is that the practice of delegated legislation is inevitably
and inextricably involved with the whole idea of governmental
intervention in the economic field, where the conditions to be regulated
are of infinite complexity and are constantly undergoing change. Granted
such intervention, it is simply out of the question to demand that
Congress should attempt to impose upon the shifting and complex scene
the relatively permanent molds of statutory provision, unqualified by a
large degree of administrative discretion. One of the major reasons
urged for governmental intervention is furnished by the need for gearing
the different parts of the industrial process with one another for a
planned result. In wartime this need is freely conceded by all; but its
need in economic crisis is conceivably even greater, the results sought
being more complex. So in the interest both of unity of design and of
flexibility of detail, presidential power today takes increasing toll
from both ends of the legislative process--both from the formulation of
legislation and from its administration. In other words, as a barrier
capable of preventing such fusion of presidential and congressional
power, the principle of the Separation of Powers does not appear to have
retained much of its original effectiveness; for on only one
occasion[31] prior to the disallowance, in Youngstown _v._ Sawyer,[32]
President Truman's seizure in April 1952 of the steel industry has the
Court been constrained to condemn, as in conflict with that principle, a
congressional delegation of legislative power. Indeed, its application
in the field of foreign relations has been virtually terminated by