A structual element for a poem would be stanzas. Hope this helped you a bit.
It would be repetition. The repetition is at the end. ("the people")
President Kennedy makes intensive use of parallelism and antithesis for the sake of persuasion and to make his speech more appealing to the audience. Antithesis is a rhetorical device which is used to contrast two ideas or things in a parallel sentence. Parallel structure is a literary device which consist of a repetition of some pattern of words. These stylistic devices offer the reader a more pleasant speech as well as it makes the speech easy to understand the main idea of the thought.
Example: "Let us never negotiate out of fear, but let us never fear to negotiate."
