** FILE ** In this Aug. 21, 1968, file photo, a Soviet tank and armored personnel carrier move into downtown Prague as part of the occupation of the Czech capital and other parts of the country by troops of Russia, Poland, Hungary, Bulgaria and East Germany. The tensions mounted quickly like a scene from the Cold War: Russia using force to quell Georgia, the United States warning that the Kremlin's behavior was "unacceptable." (AP Photo, File)