The poem describes the United States as a ship, a metaphor that Whitman had previously used in "Death in the School-Room". This metaphor of a ship of state has been often used by authors. Whitman himself had written a letter on March 19, 1863, that compared the head of state to a ship's captain. Whitman had also likely read newspaper reports that Lincoln had dreamed of a ship under full sail the night before his assassination; the imagery was allegedly a recurring dream of Lincoln's before significant moments in his life.