It is hard to ignore the political overtones of this poem and to apply what Whitman writes as an intensely personal experience to the wider political scene. Let us remember that the "self" that Whitman depicts in this poem is the epitome of Emerson's self-reliant man who captures the extremely diverse nature of America and the very many people that exist within it. Let us remember that Whitman wrote this poem at the same time as America as we know it was born as a nation with its democratic political system.
Bearing this in mind, we can consider that this poem seems to offer Whitman's solution in a curiously Transcendentalist fashion to the crisis of union that would devolve into civil war. The poem therefore, in its presentation of America and the "self" in its richest, most fullest, sense, is widely recognised as being one of the most representative works of American Literature. Note how democracy is directly refered to in the following quote:
I speak the pass-word primeval, I give the sign of democracy,
By God! I will accept nothing which all cannot have their
counterpart of on the same terms.
In poetic form, therefore, through its focus on diversity but also on the strident rights that democracy should give to all in spite of this diversity, we can consider this poem to deal explicitly with democracy and the ideals that led to the creation of America as we know it today.