The melody and the chords were worked up in a November 1983 War Tour sound check in Hawaii and completed in Windmill Lane Studios during The Unforgettable Fire recording sessions. The guitar part is subtly varied through each verse, chorus, and melody, such that no riff is exactly repeated.  The song had been intended to be based on Ronald Reagan's pride in America's military power, but Stephen B. Oates's book Let The Trumpet Sound: A Life of Martin Luther King, Jr. and a biography of Malcolm X caused the lyricist Bono to ponder the different sides of the civil rights campaigns, the violent and the non-violent. In subsequent years, Bono has expressed his dissatisfaction with the lyrics, which he describes, along with another Unforgettable Fire song "Bad", as being "left as simple sketches". He says that he was swayed by the Edge and producers Brian Eno and Daniel Lanois, who played down the need to develop the lyrics as they thought their impressionistic nature would give added forcefulness to the song's feeling, particularly when heard by non-English speakers. In U2 by U2, Bono said: "I looked at how glorious that song was and thought: 'What the fuck is that all about?' It's just a load of vowel sounds ganging up on a great man. It is emotionally very articulate - if you didn't speak English."  The song contains the erroneous reference to King's shooting as "Early morning, April 4," when it actually occurred after 6 p.m. Bono acknowledges the error and in live performances he occasionally changes the lyric to "Early evening..."  Chrissie Hynde of the Pretenders sang backing vocals on the recording. She was married to Jim Kerr of Simple Minds at the time and she is credited as "Christine Kerr".

Answer this question "Where did this song originate from?" by extracting the answer from the text above.
The melody and the chords were worked up in a November 1983 War Tour sound check in Hawaii and completed in