Final answer:
Alfred Thayer Mahan strongly believed that the US needed a strong navy in order to defend itself. Mahan argued that sea power was essential to national greatness and that a powerful navy was necessary to protect the country's merchant ships, maintain control over strategic naval bases, and secure foreign markets and raw materials.
Step-by-step explanation:
Alfred Thayer Mahan strongly believed that the US needed a strong navy in order to defend itself. Mahan argued that sea power was essential to national greatness and that a powerful navy was necessary to protect the country's merchant ships, maintain control over strategic naval bases, and secure foreign markets and raw materials. His ideas influenced policy makers and led to the expansion and modernization of the US fleet.