The Hungarian Revolution
Today marks the fiftieth anniversary of the 1956 Hungarian Revolution. The BBC has a nice interactive site, Timeline: Hungarian Revolution, for more details and Jams O’Donnell of Poor Mouth has a piece on the effect it had on the Communist Party in Britain.
Unfortunately, while the Hungarians were trying to get rid of their Communist government, Israel, Britain, and France went to war with Egypt over the Suez Crisis. While world attention was focused on the Middle East, Russia sent in a tank army and crushed the revolution.
American troops had to sit in place on the border and watch because the expected order to provide assistance to the Hungarians never came.