What did Admiral Alfred Thayer Mahan persuade the US to do ? Why?

Admiral Alfred Thayer Mahan was a distinguished American naval officer, strategist, and historian. As well as serving the Union during the Civil War, he also went on to become president of the Naval War College in Newport, Rhode Island. During his stint as a lecturer at the college Mahan wrote what would become a very influential book, The Influence of Sea Power upon History:1660-1783. Here Mahan argued for the importance of sea power in the attainment and consolidation of a nation's supremacy. At the time when Mahan wrote the book the navy was very much the Cinderella branch of the US armed forces, with fewer resources and considerably less prestige than the army.
Mahan sought to change this attitude. He became a tireless advocate of building a large and powerful navy, that as well as defending the United States from seaborne attack could also control the flow of maritime commerce, thus ensuring America's continued dominance in the global economy. Gradually, policy-makers in Washington came round to Mahan's way of thinking, becoming convinced of the importance of building a strong and powerful navy. And thanks in no small part to Mahan's influence, the United States became in due course the world's leading maritime power.