Final answer:
The last three verses of Francis Scott Key's poem reinforce his feelings of American patriotism.
Step-by-step explanation:
The last three verses of Francis Scott Key's poem clarify his feelings of American patriotism by reinforcing his patriotism. Each verse builds upon and strengthens the patriotic theme of the poem. For example, in the third verse, Key describes the American flag still waving as a symbol of victory and freedom, further emphasizing his love for his country.