Alfred Thayer Mahan (1840-1914) was an American who studied at the U.S. Naval Academy, served as a Naval Union officer during the Civil War, and became a lecturer and then President at the Naval War College, and a President in North Atlantic Squadron. During his time in the Naval War College, Mahan focused on developing studies about the influence of sea power.
Some of his main writings were The Influence of Sea Power upon History (1890) and The Influence of Sea Power upon the French Revolution and Empire (1892). These publications are mainly known for encouraging the development of navies, especially the American' navy, which was portrayed as an essential element to become an Imperial power.
In his works, Mahad held that the great powers were those that maintained strong navies and merchant marines. He also stated that the primary mission of a navy was to secure the command of the sea to secure one's own ships while denying their use to the enemy and, if necessary, closely supervise neutral trade; and that the crews of those national navies had to be thoroughly trained, and be actively aggressive when defending the nation's interests. He also supported that the production and shipping capacities had to be increased during peacetime and promoted the acquisition of repair and coaling station to the modern navies.
The United States considered that many of Mahan's points were effective for its purpose of becoming an imperial power. Consequently, Americans started to focus more on increasing their overseas possessions, enhancing its building navy plans, providing a more rigorous training for the crew, the acquisition of port facilities throughout the world, among others.