Since the end of the first world war, the USA has established itself once and for all as a great power that would not be easily defeated by anything. The rise of the USA was notable and its influence and power grew more and more each day.
In the midst of so much prosperity, the United States also cultivated enmities that would seek to attack it in every way possible. This increased the need to establish a strong defense that would protect America from adverse attacks. One way to do this was to modernize and empower the national navy, which in addition to being able to protect the United States efficiently, reaffirmed the country as the world's greatest power, both economically and militarily.
Although other presidents helped to empower the navy, it was Roosevelt who made it a symbol of US power, as a way to frighten enemies and stimulate social, political alliances with other nations and generate a strong and imposing reputation.