In the past the production of petroleum in the United States has dominated the world petroleum situation; but domestic consumption has now overtaken production, and unless discoveries of oil come along at a rapid rate the domestic deficiency seems likely to increase, with corresponding increase in our dependence on foreign sources (see pp. 128-132).
Some of the minerals of this last class, such as potash, manganese, and chromite were developed under war conditions in the United States to such an extent as to materially lessen the demand for importation; but in normal times domestic sources can supply a considerable fraction of the demand only at high cost and with the aid of a protective tariff.
No attempt will be made here to present the detailed figures on which the above generalizations are based. In view of the present disturbed conditions of production and consumption, any judgment as to future demands or available surplus must take into account several factors which cannot be accurately measured,—such as financial control in foreign countries, possible tariffs, and foreign competition. For this reason the above statement should be regarded as only tentative, though it is the result of a rather exhaustive study of conditions in relation to the world control of shipping. The classes named overlap to some extent, and it is to be expected that some of the commodities placed in one class may in the near future be transferred to another.
In terms of value, the United States has a potential export surplus of minerals about twice as large as that of all the rest of the world put together. Countries which were neutral during the war have the remaining export surplus. Great Britain, France, and Italy have net import requirements considerably in excess of their exports. Germany has almost as large a deficit of minerals as the United States has a surplus.
From the above facts it is clear that, in any scheme of international control or coöperation, the United States would have by far the heaviest stake, and perhaps the most to lose by restriction. It seems equally clear that the preponderance of exportable surplus of minerals over necessary imports justifies the United States in taking a broad and liberal view of the importation of needed minerals. The war-time necessity of making our country as nearly self-sustaining as possible does not seem to obtain in peace times. To carry that principle to an extreme means not only the expensive use of low-grade domestic supplies, but the elimination of the imports which are so necessary to balance our export trade.
These facts also raise the question as to how far the United States is justified in exploiting the rest of the world to add to its already great preponderance of control,—as, for instance, in copper. Any further aggrandizement of our position in regard to such minerals may be directly at the expense of neighbors who