Joe, the issue isn't whether something is copyright protected, as such. ASCAP is just especially pit-bull-ish in policing things like unpaid jam sessions and open mics.   

But even with "traditional" songs, it's not safe to assume someone hasn't claimed copyright on some particular "arrangement."

This is about not wanting the pub owner to get zapped with a fine from ASCAP if someone does a song that's somewhere listed with them.

And, no, I'm not looking for performers' listings (unless someone's covering their particular unique version of a song). I'm looking to see which songwriters and songs are listed.

The ACE database is helpful but it doesn't answer all my questions, partly because of duplicate names (e.g., Jimmie Rodgers) or titles (e.g., "Cupid").

Thing is, even if I know the background of a song and know it was composed well before 1922, that doesn't guarantee there's no current copyright on it or that it's not registered with ASCAP.