The Union of Soviet Socialist Republics.
When written in the Russian language, which uses the cyrillic alphabet, it comes out as CCCP
Lead country of the Warsaw Pact, even though they might not have admitted it at the time.
Broke up after Gorbachev and glasnost, leaving a load of smaller republics such as the Ukraine and Estonia to go their own way, although the Russian Federation, the rump of the USSR, is still the most powerful, most influential and got the lion's share of the nukes.
The USSR had a huge military force and were likely to be the visiting side if we ever had to play the home game.