Herman Melville, "The Armies of the Wilderness" (1866) from The Civil War: The Final Year Told by Those Who Lived It:
In my book, Kafka still has the best writerly response to war, when he noted in his diary on August 2nd, 1914 that, “Germany has declared war on Russia. Went swimming in the afternoon." But Melville has a pretty good response too in a letter to his cousin about how much he enjoyed his visit to the Wilderness/Spotsylvania area, when that would be and was one of the bloodiest encounters of the Civil War.
(Also, he goes on to express his hopes for cousin Gansevoort" "May your sword be a terror to the despicable foe, & your name in after ages be used by Southern matrons to frighten their children by." Maybe that's a bit of war-time humor, but feel free to bring that up anytime someone laments the lack of politeness and human decency these days. How often do we hear people saying "I hope you haunt their nightmares"? Maybe we should bring that back...)
Melville's poem here tells all about the war and the battle, through some scenes (e.g., a prisoner of war being asked to point out the enemy encampments) and some bird's eye commentary on the war (e.g., so terrible that only Biblical analogies of terror suffice). Frankly, the poem doesn't do much for me, largely because of Melville's almost trance-like rhythm.
But it is an interesting historical artifact. Think of it: back in the 19th century, a man could write a poem about a war and about a battle and about blood and death. I know that the Library of American has some other collections about poetry from other wars (WWI, WWII); and that if you Google "Iraq War poetry," you'll get some hits. But really, it feels like the great moment for poetry has passed by for now; these days it is relegated to high school's tragic love affairs or elementary school's cards for Mother's Day. Let's call this the infantilization of poetry.