At the close of the war with Spain it was commonly remarked that the United States had become a world power; books and periodicals written on the history of the period were based upon the assumption that America had swung out into the current of international affairs and that the traditional isolation of this country had become a thing of the past. Time must be appealed to, however, for answers to fundamental questions concerning the character of this change. Did the United States become a world power in the sense that the majority of its people threw off that policy of steering clear of permanent alliances which had been expressed by Washington in his farewell address, in favor of the policy of participation in world affairs on a footing with the larger European states? Did the people of the United States after 1898 take a constant and informed interest in world politics and international relations? Or did the people, after a slight excursion into the West Indies and the Philippines, return to the traditional attitude of "splendid isolation"? Was the extent to which the United States became a world power sufficient to make probable its entry into a European war?

A cardinal principle of the foreign policy of the United States has always been its attachment to international peace, particularly through the practice of arbitration. The great hopes raised by the two Hague Conferences were striking proofs of this fact. In 1899, at the suggestion of Czar Nicholas II of Russia, twenty-six leading powers conferred at The Hague, in order to discover means of limiting armaments and ensuring lasting peace. A second conference was held in 1907 at the suggestion, in part, of President Roosevelt. At this gathering forty-four states were represented, including most of the Latin-American republics. During the two conferences many questions relating to international law were discussed, and the conclusions reached were expressed in the form of "Conventions," which the several powers signed. In the main these agreements related to the rights and duties of nations and individuals in time of war. Most important among the agreements was one for the pacific settlement of international disputes, according to which, in certain less important controversies, the states concerned would appoint a "commission of inquiry" which would study the case and give its opinion of the facts involved. It was also agreed to organize a Permanent Court of Arbitration to be available at all times for the peaceful settlement of differences. Strictly speaking this body was not a Court, but a list of judges to which each nation was to contribute four, and when any countries became involved in a controversy they could draw arbitrators from the list. Moreover the powers agreed "if a serious dispute threatens to break out between two or more of them, to remind these latter that the Permanent Court is open to them."

The United States was a party to four of the fifteen cases presented to the Court between 1902 and 1913. The first controversy was between the United States and Mexico and involved "The Pious Fund," a large sum of money which was in dispute between Mexico and the Roman Catholic Church of California, and the second concerned claims of the United States, Mexico and eight European countries against Venezuela. As the Court was successfully appealed to in case after case, high hopes began to be entertained that the "Parliament of Man" had at last been established. Elihu Root, the Secretary of State, asserted in a communication to the Senate in 1907 that the Second Conference had presented the greatest advance ever made at a single time toward the reasonable and peaceful regulation of international conduct, unless the advance made at The Hague Conference of 1899 was excepted.

In the meantime, in 1904, under President Roosevelt's leadership, treaties were arranged with France, Germany, Great Britain and other nations, under which the contracting parties agreed in advance to submit their disputes to The Hague Court, although excepting questions involving vital interests, independence or national honor. While the Senate was discussing the treaties, it fell into a dispute with the President in regard to its constitutional rights as part of the treaty-making power, and although there was general agreement on the value of the principle of arbitration, yet the Senate insisted upon amending the treaties, whereupon the President refused to refer them back to the other nations. Secretary Root revived the project, however, in 1908 and 1909 and secured amended treaties with a long list of nations, including Austria-Hungary, France and Great Britain. President Taft signed treaties with France and England in 1911 which expanded the earlier agreements so as to include "justiciable" controversies even if they involved questions of vital interest and honor, but again the Senate added such amendments that the project was abandoned. Bryan, Secretary of State from 1913 to 1915, undertook still further to expand the principles of arbitration, and during his term of office many treaties were submitted to the Senate, under which the United States and the other contracting parties agreed to postpone warfare arising from any cause, for a year, in order that the facts of the controversy might be looked into. Many of these treaties were ratified by the Senate.