What significant concept did Alfred T. Mahan promote regarding national strength in 1890?

Alfred T. Mahan, a U.S. naval officer and historian, significantly influenced the concept of naval power as a key component of national strength in the late 19th century. In his book "The Influence of Sea Power upon History, 1660-1783," published in 1890, Mahan argued that a strong navy was essential for a nation's prosperity and security. He contended that control of the seas allowed countries to protect their trade routes, project military power, and assert global influence. Mahan's ideas contributed to a naval building spree in many countries, including the United States, leading to increased naval capabilities and competition among world powers. His emphasis on naval strength underscored its importance in shaping foreign policy and national strategy during this period of expanding American imperialism. Mahan's concepts directly informed U.S. initiatives such as the construction of a modern navy, reflecting a dramatic shift in the way national strength was perceived and acted upon.