This is about how assassinated people are treated as heroes and martyrs. Here are some of the references:
"Jack became sainted" - 'Jack' was JFK's Nickname
"Nothing's Gonna Change The World" - This is a line in The Beatles song "Across The Universe
," which John Lennon wrote.
"There was Lennon in the Happy Gun" - Another reference to John Lennon.
"We Were Looking for Mark David" - Mark David Chapman was John Lennon's killer.
Aamir - Bahawalpur, Pakistan