Whitman was an innovative American poet whose works dealt overtly with topics like sexuality while celebrating the collective experience of an idealized, democratic American life. In 1855, he published at his own expense Leaves of Grass, a volume of 12 poems. It was a commercial failure but became one of the most influential volumes of poetry in the history of American literature. Whitman’s much-recited poem “O Captain! My Captain!” was written as a tribute to what US president? Discuss