Since I don't know much modern music, but lots of random patriotic stuff:
The inauguration brought this to mind, but the Battle Hymn of the Republic is such a Jehan song, for one of those unexpectedly fierce moments. It's got loads of apocalyptic imagery ("He has sounded forth the trumpet that shall never call retreat/He is sifting out the hearts of men before His judgment seat") in the service of the cause of liberty ("As He died to make men holy, let us die to make men free"). Plus it was written by a poet/social activist who was previously known for more personal poetry.
And I can imagine Enjolras picking up via Feuilly the Greek national anthem, "Hymn to Liberty." It's addressed to liberty itself and begins,
"I recognize you by the fearsome sharpness,
of your sword,
I recognize you by the gleam (in your eyes)
with which you rapidly survey the earth."
Sounds about right.
Here day embraces night, and says: I will die with you and you will be reborn with me. From the heavy embrace of all desolations springs faith.
The real name of devotion is disinterestedness.