Opera's sweetheart Renee Fleming has been scoring her biggest emotional gains in programs featuring John Kander's "A Letter from Sullivan Ballou," a Union officer killed at Bull Run.
There is a fine YouTube presentation of same by Fleming available here (marred by some slapstick coughing). The letter itself is transcribed incompletely in some places on the web, however this version seems full.
(Note: Although Kander is a Broadway composer, the music will strike listeners ill disposed to opera as uncomfortably operatic. But if you like what you hear, listen to Paul Hindemith's and Walt Whitman's When Lilacs last in the Dooryard Bloom'd, music that should actually be the theme for the Bicentennial.)