As Commander in Chief of the Army and Navy I have directed that all measures be taken for our defense.
Ethos is when a speaker appeals to the audience's ethics. In this case President Roosevelt is showing his authority to reassure the audience that he is an expert and to be trusted in his decision to go to war with Japan. He does this by reminding the American people that his is the Commander in Chief of the Army and Navy. He also uses other types of appeal in his speech such as pathos when he appeals to the American people's emotions.