Songfacts®:

• This song is about gun violence in schools and how politicians and officials do nothing to stop it. It sets the schoolyard stage early on with a some of the children's song "The Wheels On The Bus" and the opening line:
  
  Mamas pack their lunches, kiddies pack their guns
• The title is a play on the title of an American TV series set in the Old West called Have Gun - Will Travel that ran from 1957-1963. According to Megadeth frontman Dave Mustaine, the title came to him in a dream he had where drummer Nick Menza was leaving the band and on his way out said, "Have cool, will travel."
• Unusually for Megadeth, there's a harmonica on this song. The band was getting more experimental by this point as straight-up thrash metal was falling out of favor. On the song "Trust," also from the Cryptic Writings album, they used a string section.