Answer:

SSRS

Answer	Crossword Clue
SSRS	Lat. and Ukr., once
SSRS	Ukr. and Lat., once
SSRS	Lat. and Ukr., formerly

SSRS	The Baltics, once (abbr.)
SSRS	Chevy convertibles
SSRS	Russ. units
SSRS	Latvia and Belarus, once
SSRS	The Baltics, formerly
SSRS	Ukr. and Lith., once
SSRS	Ukr. and Rus., once
SSRS	Lat. and Lith., once

SSRS	Ukr. and Lat., formerly
SSRS	Estonia and Latvia, once: Abbr.
SSRS	Former political divs.
SSRS	Belarus et al., once: Abbr.
SSRS	Cold War lands: Abbr.
SSRS	Georgia et al., once: Abbr.
SSRS	Old pol. divisions
SSRS	Former union members: Abbr.

SSRS	Russ. and Lat., once
SSRS	Some Eur. nations, not long ago
SSRS	Lith. and Ukr., once
SSRS	Lith. and Lat., once
SSRS	Ukr. et al., once
SSRS	Union mems. until 1991
SSRS	Cold war gp.
SSRS	Latvia et al., once: Abbr.

SSRS	Much of Eastern Eur., once
SSRS	Old pol. units
SSRS	Pre-1991 pol. divisions
SSRS	Lith. et al., once
SSRS	Georgia and Latvia, once: Abbr.
SSRS	Old red states?: Abbr.
SSRS	Est. and Lat., once
SSRS	Estonia and Armenia, once: Abbr.

SSRS	Old political divs.
SSRS	Red areas, once: Abbr.
SSRS	Red gp.
SSRS	Red states?: Abbr.
SSRS	The Baltics, once: Abbr.