Sudip Bose at The American Scholar:
Now the raucousness begins in earnest, as Ives renders the Independence Day parade—a drunken, lurching revel with horses on the loose and church bells clanging and a fife-and-drum corps playing intentionally off-key (recalling those lusty if decidedly amateurish New England bands Ives knew so well from his youth). There are quotations galore, some 15 of them, from such popular tunes as “Battle Cry of Freedom,” “Battle Hymn of the Republic,” “Yankee Doodle,” “Reveille,” “Marching Through Georgia,” and “Dixie,” in addition to “Columbia, Gem of the Ocean,” which the trombones deliver with gusto, though many of the tunes are distorted, distended, or truncated. All of these fragments furiously collide with each other, creating an exhilarating swirl, a feeling of polyrhythmic, harmonic chaos. The underlying philosophy here is a democratic ideal, that everything has its place in a piece of music: high art and low, consonance and dissonance, simplicity and mind-boggling complexity—everything goes. So complicated is the score that a second conductor is needed (in some performances, even a third). And in truth, Ives himself never knew if he’d ever hear this work performed. As he later wrote, “I remember distinctly, when I was scoring this, that there was a feeling of freedom as a boy has, on the Fourth of July, who wants to do anything he wants to do. … And I wrote this, feeling free to remember local things, etc, and to put [in] as many feelings and rhythms as I wanted to put together. And I did what I wanted to, quite sure that the thing would never be played, and perhaps could never be played.”
more here.