Answer:
It encourages the public to act with a united front.
Step-by-step explanation:
The repetition of the phrase "we must” helps Roosevelt achieve his purpose of encouraging the public to act with a united front. These lines are from President Roosevelt's Union Address speech. An anaphora is the repetition of the same word or words at the beginning of successive sentences in a speech. In this way, key words are emphasized and the repetition makes the ideas easy to remember.