THEODORE ROOSEVELT (1858-1919) Roosevelt’s service in the Navy Department and in the war against Spain brought out his aggressive qualities. He believed at the time that power was necessary for a country to achieve greatness, and that war was a test of superiority. He also believed that civilized nations had a right to interfere in the affairs of less advanced nations in order to improve the civilization of all. Soon after the Spanish-American War broke out tin 1898, Roosevelt helped to organize the First United States Volunteer Cavalry Regiment better known as the Rough Riders. He took command