As a child I always liked the gentle Ed McCurdy song Last Night I had the Strangest Dream, it's one my father sang fairly often, and of course was a standard for many singers of the era, including Pete Seeger, Simon and Garfunkel, John Denver, etc.

As a teen at the end of the Vietnam era I responded strongly to Edwin Starr's overt and in your face song War. (There's a digitized version of a live TV performance but it's rather broken up.)