Te-Nehisi Coates in his book, <em>Between The World And Me</em> notes the way Americans describe themselves as exceptional.
He, however, notices that the exceptionality being referred to is of intentions and not of action.
He recalls the history of America which is mired in slavery, racism, and other vices. He urges Americans to be exceptional in their actions and ways of living and not just in their intentions.
"Brennan on the Moor" is structured in this way, so that the longer stanzas can follow the tale of Brennan and give more details to the story. The shorter stanzas act as a chorus, which is usually used to come back to the main idea of a song or poem (in this case, the idea that Brennan is the hero of the poem).
