The foremost advocates of preparedness were Theodore Roosevelt and Admiral Mahan. It was little enough that they were able to accomplish, but it was more than most Americans realize. The doubling of the regular army which the Spanish War had brought about was maintained but was less important than its improvement in organization. Elihu Root and William H. Taft, as Secretaries of War, profiting by the lessons learned in Cuba, established a general staff, provided for the advanced professional training of officers, and became sufficiently acquainted with the personnel to bring into positions of responsibility those who deserved to hold them. The navy grew with less resistance on the part of the public, which now was interested in observing the advance in the rank of its fleet among the navies of the world. When in 1907 Roosevelt sent the American battleship squadron on a voyage around the world, the expedition not only caused a pleased self-consciousness at home but perhaps impressed foreign nations with the fact that the United States now counted not only as a potential but as an actual factor in world affairs. Greater popular interest, if one may judge from relative achievement, was aroused by the proposal to substitute legal for military battles. The United States had always been disposed to submit to arbitration questions which seemed deadlocked. The making of general arrangements for the arbitration of cases that might arise in the future was now advocated. The first important proposal of this character was made to the United States by Great Britain at the time of the Venezuela affair. This proposal was rejected, for it was regarded as a device of Great Britain to cover her retreat in that particular case by suggesting a general provision. The next suggestion was that made by the Czar, in 1899, for a peace conference at The Hague. This invitation the United States accepted with hearty good will and she concurred in the establishment of a permanent court of arbitration to meet in that city. Andrew Carnegie built a home for it, and President Roosevelt sent to it as its first case that of the "Pious Fund," concerning which the United States had long been in dispute with Mexico.