|IRAN: 1979, 448 days long with 3,000 plus deaths. Goal was to overthrow the Shah. Revolution started by Democrats but Islamists took over. Goal achieved.|
|TIANANMEN SQUARE, 1989.|
1989: Tiananmen. 51 days and an estimated 3,000 deaths. Goal was to establish democracy, abolish one-party rule and put an end to corruption. Goal not achieved.
1998: Indonesia. Ten days and an estimated one thousand deaths. Goal was to overthrow the oppressive regime of Suharto and abolish political cronyism. Goal achieved.
2004: Ukraine. 37 days and zero deaths. Goal was to annul a falsified election, ensure a new vote and put an end to corruption and censorship. Goal partially achieved.
2010: Tunisia. 30 days and 147 deaths. Goal: To overthrow the corrupt and unpopular regime of President Zine al-Abidine Ben Ali. Goal achieved.
2011: Egypt. 18 days and an estimated 300 deaths. Goal was to overthrow President Hosni Mubarak and about free democratic elections. Goal partially achieved.
Violent death has been the most common catalyst for radicalising discontent in the revolutions of the last 30 years. Sometimes the spark is grisly, like the mass incineration of hundreds in an Iranian cinema in 1978 blamed on the Shah's secret police.
Sometimes the desperate act of a single suicidally inflammatory protester like vegetable salesman Mohammed Bouazizi in Tunisia, in December 2010, catches the imagination of a country.
Even rumours of brutality, such as the claims the Communist secret police had beaten two students to death in Prague in November, 1989, can fire up a public already deeply disillusioned with the system. Reports that Milosevic had had his predecessor, Ivan Stambolic, "disappeared" in the weeks before the Yugoslav presidential elections in 2000 helped to crystallise Serbian rejection of his regime.
Death - though in this case non-violent - also played a role in China in April 1989, when students in Beijing hijacked the officially-sponsored mourning for the former Communist leader, Hu Yaobang, to occupy Tiananmen Square and protest against the Party's corruption and dictatorship.
Protests against Suharto's "re-election" in Indonesia in March 1998, culminated in the shooting of four students in May, which set off a round of bigger demonstrations and more violence until more than 1,000 were dead.
Thirty years earlier Suharto could kill hundreds of thousands with impunity. But corruption and the Asian economic crisis had imploded support for his regime. After 32 years in power, his family and their cronies were too rich, while too many former backers were getting poorer - a poverty they shared with ordinary people.
Tunisia's Ben Ali decided to flee when his generals told him they would not shoot into the crowds. In Romania, in December, 1989, Ceausescu lived to see the general he relied on to crush the protesters become his chief judge at his trial on Christmas Day.
External pressure plays a role in completing regime-change. In 1989, the refusal of the Soviet leader, Mikhail Gorbachev, to use the Red Army to back East European Communists facing protests in the streets made the local generals realise that force was not an option.
The United States has repeatedly pressed its authoritarian allies to compromise and then, once they have started on that slippery slope, to resign.
Longevity of a regime, and especially the old age of a ruler, can result in a fatal incapacity to react to events quickly.
Graceful exits are rare in revolutions, but the offer of secure retirement can speed up and smooth the change.
In 2003, Georgia's Shevardnadze was denounced by some as a "Ceausescu" but he was let alone in his villa after he resigned. Suharto's generals had ensured he retired to die in peace a decade later - but his son "Tommy" was imprisoned.
Often there is a hunger among people to punish the fallen rulers. Their successors, too, find retribution against the old leader can be a useful distraction from the economic and social problems, which don't disappear with the change of regime.
Other revolutions worth noting
- East Germany: Sept - Nov 1989
- Russia: 19-21 Aug 1991
- Serbia: Sep - Oct 2000
- Georgia: 2-23 Nov 2003
- Lebanon: Feb - Apr 2005
- Iran: Jun - Aug 2009
- Tunisia: 17 Dec 2010 - 14 Jan 2011
- Egypt: 25 Jan - 11 Feb 2011