The Separation of Powers
The second great structural principle of American Constitutional Law is supplied by the doctrine of the Separation of Powers. The notion of three distinct functions of government approximating what we today term the legislative, the executive, and the judicial, is set forth in Aristotle's Politics,[29] but it was the celebrated Montesquieu who, by joining the idea to the notion of a "mixed constitution" of "checks and balances", in Book XI of his Spirit of the Laws, brought Aristotle's discovery to the service of the rising libertarianism of the eighteenth century. It was Montesquieu's fundamental contention that "men entrusted with power tend to abuse it". Hence it was desirable to divide the powers of government, first, in order to keep to a minimum the powers lodged in any single organ of government; secondly, in order to be able to oppose organ to organ.
In the United States libertarian application of the principle was originally not too much embarrassed by inherited institutions. In its most dogmatic form the American conception of the Separation of Powers may be summed up in the following propositions: (1) There are three intrinsically distinct functions of government, the legislative, the executive, and the judicial; (2) these distinct functions ought to be exercised respectively by three separately manned departments of government; which, (3) should be constitutionally equal and mutually independent; and finally, (4) a corollary doctrine stated by Locke—the legislature may not delegate its powers.[30]
Prior even to Franklin D. Roosevelt this entire colligation of ideas had been impaired by three developments in national governmental practice: first, the growth of Presidential initiative in legislation; secondly, the delegation by Congress of legislative powers to the President; 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 Justice Sutherland's opinion in the Curtiss-Wright Case.[33]
The Youngstown Opinion appears to rest on the proposition that since Congress could have ordered the seizure, e.g., under the necessary and proper clause, the President, in making it on his own, usurped "legislative power" and thereby violated the principle of the Separation of Powers. In referring to this proposition, the Chief Justice (in his dissenting opinion, for himself and Justices Reed and Minton) quoted as follows from a 1915 brief of the then Solicitor General of the United States on this same question:
The function of making laws is peculiar to Congress, and the Executive can not exercise that function to any degree. But this is not to say that all of the subjects concerning which laws might be made are perforce removed from the possibility of Executive influence. The Executive may act upon things and upon men in many relations which have not, though they might have, been actually regulated by Congress.
In other words, just as there are fields which are peculiar to Congress and fields which are peculiar to the Executive, so there are fields which are common to both, in the sense that the Executive may move within them until they shall have been occupied by legislative action. These are not the fields of legislative prerogative, but fields within which the lawmaking power may enter and dominate whenever it chooses. This situation results from the fact that the President is the active agent, not of Congress, but of the Nation.[34]
Or, in more general terms, the fact that one of the three departments may apply its distinctive techniques to a certain subject matter sheds little or no light on the question whether one of the other departments may deal with the same subject matter according to its distinctive techniques. Indeed, were it otherwise, the action of the Court in disallowing President Truman's seizure order would have been of very questionable validity, inasmuch as the President himself conceded that Congress could do so.