Since I do not know when this poem was written, I can't place in the context of the so-called MANIFEST DESTINY policy of the United States government and society. Americans today do not appreciate the glaring IMPERIALISM of this national policy which took for granted the USA would become a continental nation. In Europe notions far less grandiose caused years of warfare and contested borders and eventually two World Wars in the 20th century. The USA was spared such violence because the opposition was primarily Native Americans. However much I revere Whitman, I cannot get on this band wagon.
Those of us most powerfully drawn by this impulse have arrived at the very edge of the Western Sea and pile up massively together, Los Angeles, San Diego, San Jose, San Francisco. Where now, dear Walt?