[notzorbo2]

  You’re the one who
  must decide who’s
  to live and who’s to die.
  You’re the one who gives his
  body as a weapon of the
  war—and without you all
  this killing can’t go on.

That's from the Donovan song "Universal Soldier" (original by Buffy Sainte-Marie). Looks like some historian published it as a “mystery poem” in the Smithsonian magazine[1], not realizing it was just quoting song lyrics.

¹ http://buffysainte-marie.com/?p=809