of the country, and adapt themselves to the new developments of time and circumstances." Hence Congress had previously designated canals, waterways, plank roads, railroads, highways, letter-carrier routes, and telegraph lines across public roads as post roads (39 U. S. C. A. 481, 482 and 43 U. S. C. A. 959-961), and finally it declared that "all air routes which are now or may hereafter be in operation" are post roads as well (39 U. S. C. A. 481).

The power to establish post roads has been so construed as to repose in Congress the power to establish such roads, to facilitate the safe and speedy transit of the mails thereon, and to protect the mails from obstruction. Knowingly and wilfully to obstruct the mails, for example, has been expressly declared by Congress to be a misdemeanor (18 U. S. C. A. 324). And it has been decided that the placing of obstructions on the track of an electric railroad carrying mail is a violation of the statute if such act makes it necessary to delay the mails, or carry them in a different fashion (U. S. v. Thomas (1893), 55 Fed. 380.) While the decisions announcing the scope of the postal power, as compared with those construing the powers of Congress under the commerce clause, are few in number, they appear rather clearly to point to the conclusion that Congress by virtue of the postal power alone is authorized through zoning regulations to forbid and order the removal of hazards in the form of ground obstructions to the air transportation of the mails, even had no interstate commerce or war powers been granted by the Constitution. It has already been noted, however, that by virtue of the tremendous scope of the commerce power, no extensive examination of the scope of the postal power is required.

B. THE WAR POWER

While the powers to make war, and to carry war to a successful conclusion, are the broadest special powers conferred on Congress, there are few cases which discuss their practical extent. The courts have regularly said that these powers are subject to the limitations contained in the Bill of Rights, but clearly there are no other limitations. The term "to declare war" connotes the plenary power to wage war and wage it effectively. The authority to "declare war," in other words, extends to the enactment of all legislation necessary to a successful prosecution of a war. It includes, as circumstances demand, the authority to use other means than those directly inferable from the express grant of power and contemplates all of the methods by which war may be successfully prosecuted. That the needs of the present conflict require every effort of the Federal Government to clear the airfields of obstructions and hazards to military flights is obvious. Unquestionably Congress can enact such measures at this time under its war powers. But even in the coming peace, defense needs will require that Congress maintain an Army and Navy, and take steps to see that the armed forces are properly trained, supplied, and transported. At that time, no less than now, it will be within the power of Congress to take any action necessary to safeguard the personal safety of the men serving in the armed forces and to provide for the adequate protection of all transportation facilities necessary for the national defense.

The extent to which the Supreme Court has sustained zoning laws, enacted under the war powers, whose purpose was the protection of the health and safety of men in the services, is shown by the decision in McKinley v. U. S. ((1918) 249 U. S. 397). There the Court upheld that section of the draft law of 1917 which authorized the Secretary of War to zone the area around military encampments and by regulation to prohibit prostitution and other immoralities therein. The Court had so little doubt as to the validity of this enactment under the war power that it indulged a memorondum opinion.

Had it not been for the war power, of course, the measure would clearly have been an invasion of the reserved powers of the States, since such zoning laws are traditionally considered as local police measures not delegated by the Constitution to the Federal Government.

Disregarding for the moment the force of the postal and the commerce powers, it could hardlly be argued that the proposed provision, though a valid exercise of the war power during the present conflict, would cease to be germane to that power at the conclusion of the war. A realistic regard to the defense needs of the country during the years following the war, and the vital importance of adequate and unobstructed landing areas to military defense requirements should amply convince that such an objection would be entirely without substance. The extent to which the Court has gone in holding statutes germane

to an exercise of the war powers is shown in Brooks-Scanlon v. U. S. ((1924) 265 U. S. 106). There the act of Congress had authorized the condemnation of land, with compensation, for the erection of monuments on the Gettysburg battlefield. The Court upheld the act as germane and appropriate to the exercise of the war-making power, especially in view of the fact that it tended to enhance the love of a citizen for his country and to quicken his motives to defend it.

It may be concluded, then, that the Congress ably has the power to pass this provision as a provision for national defense.

C. THE COMMERCE POWER

Both the postal and the war powers have been said to be plenary and, excepting only the limitations contained in the Constitution itself, are without boundary in their fields of operation. While both are special powers, when they combine with the power conferred by the commerce clause, they assumé an almost unlimited scope. The convergence of these three powers as a basis for a single enactment such as that now proposed, in other words, should be sufficient to render the provision proof against any suggestion that it lacks a constitutional basis.

From the beginning the power over interstate commerce has been given a liberal construction, and broad and flexible interpretations of its scope have been consistently maintained. As Chief Justice Stone said in United States v. Darby Lumber Co. ((1941) 312 U. S. 100, 115), one of the most recent cases construing the extent of this power, "Whatever their motive and purpose, regulations of commerce which do not infringe some constitutional prohibition are within the plenary power conferred on Congress by the commerce clause." In the earlier case of National Labor Relations Board v. Jones & Laughlin Steel Corp. ((1937) 301 U. S. 1, 36), Chief Justice Hughes had announced the same principle somewhat more elaborately:

The fundamental principle is that the power to regulate commerce is the power to enact “all appropriate legislation" for "its protection and advancement" * * * to adopt measures "to promote its growth and assure its safety" "to foster, prohibit, control, and restrain. ** That power is plenary and may be exerted to protect interstate commerce "no matter what the source of the dangers which threaten it."

* * *.

Aside from the question of the power of Congress to regulate otherwise local activities which affect or burden commerce, the Court's extremely liberal application of the concept of directly "engaging in commerce" is demonstrated by its very recent decision in Overstreet v. North Shore Corporation (87 L. Ed. 423), decided February 1, 1943. There it was held that employees engaged in the operation of a toll bridge which supported motor traffic were "engaged in commerce" within the coverage of the Fair Labor Standards Act.

In the light of the Supreme Court's view that the power of Congress is practically without limit it is rather difficult to anticipate arguments which might be advanced against the existence of the power to enact the present provision. Any argument that the proposed sections are beyond the power of Congress to enact, because in prescribing the conditions under which real estate is to be held they are directed to matters purely local, would be entirely without support in the cases. Such an argument would necessarily ignore the very real burden which is imposed upon air commerce by hazardous obstructions in the vicinity of landing areas.

It is established beyond question that where Federal regulation cannot be applied to protect interstate commerce without affecting intrastate transactions, the Federal regulaion must be applied to the whole. Thus in Sotuhern Ry. Co. v. United States ((1911) 222 U. S. 20), the Court upheld the Safety Appliances Act which prescribed safety standards to be met by railroad cars and equipment moving both in interstate and intrastate commerce. The cars over which the Federal Government had exerted jurisdiction were moving in commerce that was completely within the State. The Court held that the act must necessarily apply to the same and similar cars moving in intrastate commerce, the safety of the interstate commerce being dependent upon the use of the same safety appliances throughout the railway system. This decision was closely followed in the Shreveport case ((1914) 234 U. S. 342), in which the Court laid down the

rule that the Federal Government has power to regulate both the interstate and the intrastate rates of a carrier where the two rate structures are so interdependent that regulation of intrastate rates is necessary for the complete protection of interstate commerce. The same principle contributed largely to the decisions in National Labor Relations Board v. Jones & Laughlin Steel Corp., ((1937) 301 U. S. 1) and United States v. Darby Lumber Co. ((1941) 312 U. S. 100), in which the constitutionality of the National Labor Relations Act and the Fair Labor Seandards Act, respectively, was upheld. In both decisions it was announced that Congress is not confined under the commerce power only to regulations of the "stream" or "flow" of commerce; Congress may prescribe fair labor practices and fair labor standards for local manufacturing employments which, were it not for their effect upon commerce, would be exclusively subject to the jurisdiction of the States.

The practically unlimited sweep of the commerce power resulting from the application of the doctrine announced in the Shreveport case is strikingly demonstrated in two recent cases: United States v. Wrightwood Dairy Co. ((1942) 315 U. S. 110), and Wickard v. Filburn ((1942) 87 L. Ed. 57). In the Wrightwood case it was held that the Secretary of Agriculture had power under the Agricultural Marketing Agreement Act, and by virtue of the commerce clause, to regulate the marketing of milk produced, sold and consumed entirely within the State of Illinois. The facts were that (pp. 117-118) :

In the course of its business [respondent] purchases milk from producers within the State of Illinois, processes the milk and sells it in the State "in competition with milk of other handlers in the area"; that none of respondent's milk is physically intermingled with that which has crossed State lines * * *

The lower courts, which had held such local marketing to be beyond the power of the Federal Government to regulate under the commerce clause, were reversed for the reasons, as stated by the Court (p. 120) that—

The marketing of a local product in competition with that of a like commodity moving interstate may so interfere with interstate commerce or its regulation as to afford a basis for congressional regulation of the intrastate activity. It is the effect upon the interstate commerce or its regulation, regardless of the particular form which the competition may take, which is the test of Federal power.

And in Wickard v. Filburn, supra, it was held that under the commerce clause a farmer might be penalized for growing wheat on his farm in excess of a quota fixed under the Agricultural Adjustment Act, even though such wheat was raised and was used for the purpose of feeding the farmer's livestock on the farm. But the power of Congress to reach behind the actual stream of commerce in order to eliminate hindrances to its movement is not limited to regulations of transactions, activities, and business practices. Congress may forbid the erection, as well as require the removal of physical impediments to the interstate movement of goods and the free passage of interstate instrumentalities. There is a long line of cases which have established the principle that the commerce clause empowers Congress not only to maintain and improve the navigability of the waterways of the United States by positive Federal action, but also to protect such waterways against hazards and obstructions impeding or endangering their use. A typical announcement of the principle followed in these cases may be quoted from Ashwander v. T. V. A. ((1936) 297 U. S. 288, 326): "The power to regulate interstate commerce embraces the power to keep the navigable rivers of the United States free from obstructions to navigation and to remove such obstructions when they exist."

Thus Congress under the power to regulate commerce may create a corporation to build a bridge across navigable waters and acquire private lands for this purpose, Luxton v. North River Bridge Co. ((1894) 153 U. S. 525); it may erect dykes, Gibson v. United States ((1897) 166 U. S. 269); construct piers, Scranton v. Wheeler (1900) 179 U. S. 141); conduct dredging operations, Lewis Blue Point Oyster Co. v. Briggs ((1913) 229 U. S. 82); condemn, acquire and develop entire rivers, United States v. Chandler-Dunbar Co. ((1913) 229 U. S. 53); fix harbor lines beyond which the building of wharves, docks, or other obstructions to navigation may be made a crime, Greenleaf 83838-43-17

Lumber Co. v. Garrison ((1914) 237 U. S. 251), Philadelphia Co. v. Stimson ((1911) 223 U. S. 607); require the removal at a railroad's expense of a tunnel beneath a river, West Chicago Railroad v. Chicago ((1906) 201 U. S. 506); require the alteration or removal at the owners expense of a bridge built over navigable waters, Union Bridge Co. v. United States ((1906) 204 U. S. 364); and condemn and acquire locks and dams on navigable streams. Monogahela Navigation Co. v. United States ((1893) 148 U. S. 312).

The recent case of United States v. Appalachian Power Co. ((1940) 311 U. S. 377), has extended the concept of navigability farther than any of its predecessors. Here it was held to be within the power of Congress to require a license from the Federal Power Commission for the construction of a dam in the New River, which flows through Virginia and West Virginia. The portion of the stream in question was not used for navigation at the time and would not be suitable for navigation without considerable improvement. The court held nonetheless that this portion of the stream was "navigable" and hence within the power of Congress to regulate since (p. 407): "A waterway, otherwise suitable for navigation, is not barred from that classification merely because artificial aids must make the highway suitable for use before commercial navigation may be undertaken." The following extract is of interest. At p. 426:

In our view, it cannot properly be said that the constitutional power of the United States over its waters is limited to control for navigation. By navigation respondent means no more than operation of boats and improvement of the waterway itself. In truth the authority of the United States is the regulation of commerce on its waters. Navigability, in the sense just stated, is but a part of this whole. Flood protection, watershed development, recovery of the cost of improvements through utilization of power are likewise parts of commerce control. It may well be that this portion of the river is not needed for navigation at this time. Or that the dam proposed may function satisfactorily with others, contemplated or intended. It may fit in as a part of the river development. The point is that navigable waters are subject to national planning and control in the broad regulation of commerce granted the Federal Government.

* * *

Finally, the Court held in Oklahoma v. Atkinson ((1941) 313 U. S. 508) that it was within the power of Congress to construct dams even upon streams which were not either navigable in fact or potentially navigable with improvement, if it could be shown that the condition of such a stream affected the navigability of another stream to which it was tributary. The Court said (p. 525):

* * *

There is no constitutional reason why Congress cannot under the commerce power treat the watersheds as a key to flood control on navigable streams and their tributaries. Nor is there a constitutional necessity for viewing each reservoir project in isolation from a comprehensive plan covering the entire basin of a particular river We have recently recognized that "flood protection, watershed development, recovery of the cost of improvements through utilization of power are * * * parts of commerce control." [Citing the Appalachian case.] And we now add that the power of flood control extends to the tributaries of navigable streams.

It is thus fair to conclude that the power of Congress under the commerce clause to protect, develop, regulate, and control the navigable waters of the United States, and even their tributaries and watersheds, is practically, if not entirely, without limit. If the commerce clause applies with equal potency to air navigation, no doubt can be entertained concerning the power of Congress to enact the proposed zoning provisions.

Any contention that the commerce clause possesses varying degrees of efficacy depending upon the nature or medium of interstate transportation involved must necessarily rest upon an absolutist assumption that one means of interstate transportation is somehow in the nature of things more "interstate" under the Constitution than another. There is, of course, no warrant for such an assumption, and any pretensions which it might make to legal recognition were thoroughly shattered by the Court more than 50 years ago in Monongahela Navigation Co. v. United States ((1892) 148 U. S. 312). There the Court said (p. 342):

The power which Congress possesses in respect to this taking of property springs from the grant of power to regulate commerce; and the regulation of commerce implies as much control, as far-reaching power, over an artificial as over a natural highway. They are simply the means and instrumentalities of commerce, and the power of Congress to regulate commerce carries with it power over all the means and instrumentalities by which commerce is carried on. There may be differences in the modes and manner of using these different highways, but such differences do not affect or limit that supreme power of Congress to regulate commerce, and in such regulation to control its means and instrumentalities. We are so much accustomed to see artificial highways, such as common roads, turnpike roads, and railroads constructed under the authority of the States, and the improvement of natural highways carried on by the general government, that at first it might seem that there was some inherent difference in the power of the National Government over them. But the grant of power is the same. There are not two clauses of the Constitution, each severally applicable to a different kind of highway. The fee of the soil in neither case is in the general government, but in the State or private individuals. The differences between the two are in their origin-nature provides the one, man establishes the other. [Italics added.]

The Court's pronouncement, directed against the position that the power of Congress under the commerce clause is somehow more extensive with respect to navigable waters than it is with respect to artificial highways, equally rejects any contention that the power of Congress is any the less in the case of air navigation than it is with regard to water navigation. Indeed, the analogy of air transportation to water transportation is closer than is the analogy of land transportation, since in both air and water nature provides the medium, while highways for land travel, as the Court states, are established by man.

Hence the analogies furnished by the cases declaring the plenary and unlimited power of Congress to protect commerce on the navigable waters of the United States are fully applicable to establish the constitutionality of congressional regulation and prohibition of hazards to air commerce in the form of obstructions in the vicinity of landing areas and elsewhere.

II. LIMITATIONS OF THE FIFTH AMENDMENT

Assuming the existence of the power of Congress to enact the proposed zoning provisions, the question remains whether and in what circumstances compensation must be paid to the landowner affected. If and when compensation is required, the requirement arises by virtue of the injunction of the fifth amendment: "Nor shall private property be taken for public use, without just compensation."

Before any detailed consideration of the due-process requirements, it would be well briefly to outline the concept of eminent domain. There is no provision of the Federal Constitution expressly delegating to the United States this. power, although the portion of the fifth amendment quoted above might be said to imply its existence. The Supreme Court has held the power to exist for the reason that "the right is the offspring of political necessity; and it is inseparable from sovereignty unless denied to it by its fundamental law." Kohl v. United States ((1875) 91 U. S. 367, 371).

Both the States and the Nation possess this power as a necessary incident of sovereignty. They are, however, limited in its exercise by the requirement, among others, that the property taken be taken for a public use. In the case of the Federal Government this requirement is satisfied if the exercise of the power is necessary for the accomplishment of an object within the scope of an expressly delegated Federal power. As the Court stated in Luxton v. North River Bridge Co. ((1894) 153 U. S. 525, 529):

* *

The Congress of the United States, being empowered by the Constitution to regulate commerce among the several States, and to pass all laws necessary or proper for carrying into execution any of the powers specifically conferred, may make use of any appropriate means for this end. * And whenever it becomes necessary, for the accomplishment of any object within the authority of Congress, to exercise the right of eminent domain and take public lands, making just compensation to the owner, Congress may do this, with or without a concurrent act of the State in which the lands lie.