This Land is Your Land would be a suitable choice for the Progressives, given that it was written by a communist, Woody Guthrie.
America the Beautiful is a hymn. Verse three:
O beautiful for heroes proved
In liberating strife,
Who more than self their country loved
And mercy more than life!
America, America May God thy gold refine,
Til all success be nobleness,
And ev’ry gain divine.