Possible Clues:

• Much of Eur., once
• Armenia and Georgia, once
• Union members until 1991: Abbr
• Lat. and Est., once
• Some old Eur. republics
• States in an outdated atlas: Abbr
• Ukr. and Est., once
• Pol. units until 1991
• Historical group of 15, for short
• Georgia and others, once: Abbr