When the Spanish-American War was declared, Mark Twain wrote new words to the Battle Hymn of the Republic. I heard them read by Garrison Keillor: he broadcast The American Radio Company of the Air from Twain's house in Hartford, on December 1, 1990, and I heard a rebroadcast in the Summer of 1991.
Thanks to ASpanos747, I now know one place where the lyrics have been published:
Twain, Mark. 1917. The complete works of Mark Twain, vol. 20, page 465. New York: Harper Brothers.
If anyone knows where and when Twin's lyrics were first published, please let me know at firstname.lastname@example.org
Mine eyes have seen the orgy of the launching of the Sword:
He is searching out the hoardings where the Stranger's wealth is stored.
He hath loosed his fateful lightnings and with Woe and Death has scored.
His lust is moving on.
In a sordid slime harmonious Greed was born in yonder ditch,
With a longing in his bosom and for others' goods an Itch.
As Christ died to make men holy, let men die to make us rich;
Our God is marching on.