In 1920, Van Wyck Brooks wrote that Whitman was the "focal center" of American creative experience and literary expression. The poet combined within him elements of native realism and of New England philosophy which made him a truly national spiritual synthesis. But modern criticism does not view Whitman as the quintessential American poet, or the national norm; other writers, such as Emerson, Thoreau, Melville, and Hawthorne may be equally regarded as national norms. Whitman, no doubt, embodied many qualities of the American character — for example, its variousness, diversity, adventurousness, and pioneering spirit — yet he was not the only national norm. To us today, submerged as we are in specialization, Whitman has a particular appeal because he symbolizes variety, largeness, and the tendency toward innovation.
Walt Whitman's achievement as a poet and prophet is truly monumental. He exercised a deep influence on his immediate successors in American letters, and even on modern poets, although he himself was a highly individualistic poet. As a symbolist, his influence was felt in Europe, where he was considered the greatest poet America had yet produced. His high style and elevated expression found echoes in Emily Dickinson, Hart Crane, Marianne Moore, and others. Whitman as a stylist is the culmination of the sublime tradition in America, and even Allen Ginsberg, so different from Whitman in so many respects, follows the Whitman tradition of using invocative language. Whitman, though a man of his age, an essentially nineteenth-century poet, exercised a profound influence on twentieth-century poets and modern poetry in the use of language, in the processes of symbol and image-making, in exercising great freedom in meter and form, and in cultivating the individualistic mode. In many ways Whitman is modern because he is prophetic; he is a poet not only of America but of the whole of mankind. He has achieved the Olympian stature and the rare distinction of a world poet.