1. Who or what does the siren stand for?
             In ancient Greek mythology, the sirens were non-human, and stranger creatures, dwelt on dangerous rocks and sang irresistible songs that lured unsuspecting sailors to their death by shipwreck. They appealed to be helpless beautiful women in need of rescuing. This would appeal to the sailors' heroic inclination and play their sense of loneliness. Because of sailors' lapse in judgment, they will lose their lives.
             In the modern society, there are various forces at work that act as sirens. One prominent "siren" and one that is hinted at in the poem is nationalism. Countries send out a call to their young people, especially. "Be all that you can be", for example, is a slogan that makes people feel unique and valuable. The idea is to put across that one can be heroic and righteous even though they see the "beached skulls" (line 6) and still "jumped overboard of squadrons." (line 5)
             As the read reads the poem, he feels same sense of invulnerability ---surly he will not suffer from the dire consequence of hearing the song. Using our previous example of nationalism, we can see how this works in the real life. Young men going off to war are generally taken by the idea that they will be heroes, somehow rescuing the piece of land, defined at that moment as their country. Just as anyone how hears the poetic siren song dies, in real life, anyone who hears the siren song of nationalism dies in either physical or spiritual sense since they take part in the work of killing and violence for no defensible reasons.
             Certainly, besides nationalism, there are other siren songs, such as materialism, or mismatched love, etc. The idea of the siren song represents anything that promises much, but ends up in ruin.
             2. How does the poem change tone and what does it accomplish?
             The first line is captivating with no sense of danger. It makes the re...