The Tunisian and Egyptian political eruptions were pretty much totally unexpected by the governments of the United States and of other countries, and by the vast majority of experts on Egypt and the Islamic world. To be sure, experts were aware that the government of say Egypt was not popular among many segments of the population, including The Muslim Brotherhood, most intellectuals, and many members of the growing middle class. However, the timing and speed of the uprising there (and in Tunisia) was rather a complete surprise since Mubarak and Ben Ali were in power for over 20 years, and seemingly in rather complete control.
I was first impressed by the unexpected and speedy nature of the overthrow of authoritarian regimes in 1979 when a combination of religious and leftwing groups forced the Shah of Iran from power. Until very close to the end he looked invulnerable: he seemed to be in full control of a strong and well-equipped army, and had an active and dreaded secret police, the SAVAK, that imprisoned anyone who vocally attacked the government. That the overthrow was unexpected is objectively measured by the stability of the international value of the Iranian currency, the rial, until just a few weeks before the Shah was ousted. Had the overthrow been anticipated, the value of the currency would have plunged as Iranians and others tried to get out of rials into dollars and other hard currencies. The rial did plunge in value shortly after the revolution appeared to be succeeding.
The rapid disintegration of the Soviet Union is another telling example. In 1989 my wife and I took a train from West Berlin through East Germany to go to Warsaw. The customs agents in East Germany were unpleasant, and the East German government headed by Erich Honecker seemed totally in charge. Much to my surprise, less than six months later, close to one million younger men and women were demonstrating in the streets, and the government was soon quickly gone, along with most of the Russian empire.
(photo credit: Maggie Osama)