Well, (in some sort of order) Sandy- We do have several songs from the Bosses' Songbook in the DT, and will have more in the future. Also some from the U of Chi's Person's Songbook (ca 1949).
Leaving out Child, who really wasn't a collector, most of the great collectors had a definite leftish bent, getting more pronounced as we progressed from Sharp thru Lomaxes and Seegers. I've been conucting a quiet campaign to seek out traditional songs from the "wrong" side---Irish Orange songs, American Tory songs, anti-union songs---with but moderate success, though I've seen references to them. There are a lot of splinter group songs from the 20's through the 60's attacking Communists, usually from the standpoint of Socialists, Trotskyites and other left-wing non-conformists.