POP was a new type of music, and people loved it. This event happened during the Vietnam war, where the US fought against Vietnam. This war affected the pop directly. Musicians made songs supporting the US, and its army, in the Vietnam war (as The Ballad of the Green Berets) and others made songs that demanded the end of the war. These songs complaint mostly about the draft and forms of dodging or avoiding the draft. The draft was the process of selecting people to fight in the war. The draft was unfair specially for young people because they were sent to fight as soldiers. Songs as Fortunate Son blame this unfair situation.
The Vietnam war lasted from 1955 to 1975.
John Fitzgerald Kennedy, the current president in the 60s was assassinated in 1963. Most people loved Kennedy and his assassination painted in black the US.
All these happenings also affected the POP in a less direct way. Songs became depressive, with a sad tone.
But not all the events were awful. On July 21st 1969, Neil Armstrong became the first human being walking on the moon. He was American, which meant that the US was ahead in the space race until that moment. The POP was born for a second time with this topic of the moon and the victory of the space race (The moon song).