Just finished Robert Caro's Working, which is a collection of pieces about how he writes and wrote the Robert Moses bio and the four volumes on LBJ. It's good. interesting to anyone who's read one or more of his books, and/or lived through the 50's and 60's.
One of the pieces discusses two songs he sees as key to the 60's, one being Seeger's "Waist Deep in the Big Muddy" (anti-Vietnam).
To me the other song, which of course is "We Shall Overcome" has faded a bit, to be replaced or challenged as an iconic song by "Amazing Grace". I see a contrast in the two which might reflect the changes in American history from the 50's to the teens.
"We Shall Overcome" is a song of reform and solidarity. "Amazing Grace" is a song of individual redemption. IMHO the old structures of society I knew in the 50's have dissolved or changed from the impact of the boomer generation and social movements, so the individual is now more important than ever.
I'd suggest that before my adult years national songs were more often the patriotic songs, the ones I learned in school. I understand that formal music instruction in K-12 is less common than it used to be, but a study comparing the songs taught now versus then would be interesting.