This book examines President Theodore Roosevelt’s use of the United States naval services as supporting components of his diplomatic efforts to facilitate the emergence of the United States as a Great Power at the dawn of the 20th century. After reviewing the development of Roosevelt’s personal philosophy with regard to naval power, the book traverses four chapters that reveal Roosevelt’s use of the Navy and Marine Corps to support American interests during the historically controversial Venezuelan Crisis (1902-03), Panama’s independence movement (1903), the Morocco-Perciaris Incident (1904) and the choice of a navy yard as the sight for the negotiations that ended the Russo-Japanese War. The voyage of the Great White Fleet and Roosevelt’s actions to technologically transform the American Navy are also covered. In the end the book details how Roosevelt’s actions combined to thrust the United States forward onto the world’s stage as a major player, and cemented T.R’s place in American history as a great president despite the fact that he did not serve during a time of war or major domestic disturbance. This history provides new information that finally lays to rest the controversy of whether Theodore Roosevelt did or did not issue an ultimatum to the German and British governments in December, 1902, bringing the United States to the brink of war with two of the world’s great powers. It also reveals a secret war plan developed during Panama’s independence movement which envisioned the United States Marine Corps invading Colombia to defend the sovereignty of the new Panamanian republic.