Egads!   So many choices from so many eras. I am going with Eve of Destruction by Barry McQuire. It came out the year I was born. I just remember my much older siblings and neighborhood peers listening to it and talking about Nam in the early 1970’s.

Somehow it is fitting for the current state of the world.

And yes, sound of silence is a great song. 
https://youtu.be/qfZVu0alU0I?si=pGmpR_uA3Gq0Ca9A