The dangerously aggressive tendency of the Monroe Doctrine is not due to the fact that it derives its standing from the effective military power of the United States.  The recognition which any proclamation of a specific principle of foreign policy receives will depend, in case it conflicts with the actual or possible interests of other nations, upon the military and naval power with which it can be maintained.  The question as to whether a particular doctrine is unwholesomely aggressive depends, consequently, not upon the mere fact that it may provoke a war, but upon the doubt that, if it provokes a war, such a war can be righteously fought.  Does the Doctrine as usually stated, possibly or probably commit the United States to an unrighteous war—­a war in which the United States would be opposing a legitimate interest on the part of one or a group of European nations?  Does an American foreign policy of the “Monroe Doctrine and the Golden Rule” proclaim two parallel springs of national action in foreign affairs which may prove to be incompatible?

There is a danger that such may be the case.  The Monroe Doctrine in its most popular form proclaims a rigid policy of continental isolation—­of America for the Americans and of Europe for the Europeans.  European nations may retain existing possessions in the Americas, but such possessions must not be increased.  So far, so good.  A European nation, which sought defiantly to increase its American possessions, in spite of the express declaration of the United States that such action would mean war, would deserve the war thereby incurred.  But there are many ways of increasing the political influence of European Powers in the Americas without actual territorial appropriation.  The emigration from several European states and from Japan to South America is already considerable, and is likely to increase rather than diminish.  European commercial interests in South America are greater than ours, and in the future will become greater still.  The South Americans have already borrowed large quantities of European capital, and will need more.  The industrial and agricultural development of the South American states is constantly tying them more closely to Europe than it is to the United States.  It looks, consequently, as if irresistible economic conditions were making in favor of an increase of effective European influence in South America.  The growth of that influence is part of the world-movement in the direction of the better utilization of the economic resources of mankind.  South America cannot develop without the benefits of European capital, additional European labor, European products, and European experience and training; and in the course of another few generations the result will be a European investment in South America, which may in a number of different ways involve political complications.  We have already had a foretaste of those consequences in the steps which the European Powers took a few years ago to collect debts due to Europeans by Venezuela.