According to Delta, the A319 has an effective range of 2,399 miles. Since ATL is the closest hub to SA, let's assume they will commence the A319 operations from there.
These are the current routes that would work (northern south america):
AUA
BON
CCS
BOG
UIO
All the other routes are too far. Currently, it seems those routes are services by the 737 or the 757 now.