Lyric discussion by laurens re 

Cover art for Why We Build the Wall lyrics by Anaïs Mitchell

This song was written in the 2000's for the music theater piece Hadestown, in which the character of Hades uses this song for indoctrination.

Anaïs Mitchell wrote a nice piece for The Huffington Post in 2016, explaining the songs origins and noting its uncanny political relevance in anticipation of the 2016 US presidential election:

"(...) America, too, has a choice coming up. I’ve taken to saying, when I play “Why We Build the Wall” now at my own shows: “This song is ten years old… Any resemblance of any contemporary political figures to the King of the Underworld is purely coincidental.”

But we all know the Underworld Boss/King archetype when we see him. Let’s not elect him President."