By Dominic Evans
BEIRUT (Reuters) - The first fled to exile, the second is on trial and the third Arab ruler to be toppled in an Arab revolt died at the hands of rebels he once dismissed as rats.
The killing of Muammar Gaddafi sends a bleak message to Syrian and Yemeni presidents still resisting demands for change that the longer they hold out, the higher the price of failure.
Tunisia's leader Zine al-Abidine Ben Ali and Egypt's Hosni Mubarak both stepped down within a few short weeks of mass protests breaking out against them.
But Syria's President Bashar al-Assad shows no sign of yielding to seven months of unrest, and protesters who called at first for political reform of his tightly controlled Arab country are now openly chanting for his execution.
Yemeni President Ali Abdullah Saleh, who reneged three times on pledges to hand over power, has already survived an assassination attempt which forced him briefly into exile for medical treatment.
Gaddafi's killing "sends a message for the presidents and the entourage around them -- what fate awaits us even if we are prevailing now?" said Ibrahim Seif, resident scholar at the Carnegie Middle East Center in Beirut.
For months Gaddafi had the option of seeking safe haven in sympathetic African countries, Seif said, but chose to stand his ground against a rebel force which, backed by NATO jets, gradually turned the tide against his forces and eventually defeated and killed him.
Neither Assad nor Saleh yet faces the prospect of foreign military intervention, but the longer their standoffs with protesters continue, the smaller the prospect of any deal to end the unrest.
"Some people are now saying that Zine al-Abidine and Mubarak were wise men for leaving in that way," Seif said.
Even if the Yemeni and Syria leaders were determined to stay in power, their close supporters might have second thoughts, he added. "When they see total collapse they have to think twice about what they are doing."
Successive gains by Libyan rebels, from the capture of the capital Tripoli in August to Gaddafi's killing on Thursday, have been closely monitored elsewhere by protesters and presidents alike.
"Dictators share the same habits and traits -- every time one of their own falls, the others take notice," said Yemeni political analyst Abdulghani al-Iryani. "This will have a big political impact on President Saleh."
But the veteran Yemeni leader is unlikely to be pushed into a dramatic change of strategy.
"Saleh is now calibrating his response. It will be a game of combining military pressure with calls for negotiations," Iryani said. "If things seem to be going his way he will increase military pressure, but if they seem to worsen for him he will open more to reconciliation."
Hafedh al-Buqari, an analyst and president of the Yemen Polling Center, said Gaddafi's death would frighten Saleh but might drive him to be "more stubborn against international pressure" to stand aside.
"Saleh is looking for the fourth option -- the Yemeni option without fleeing or dying. He thinks he can cling to power," he said.
In some Arab countries, where rulers face calls for reform rather than regime change, the bloody end to Gaddafi's 42-year hold on power could still encourage attempts at compromise.
"In Jordan, Morocco and Bahrain, they still have room to maneuver... and I think what happened to Gaddafi will accelerate the process of them engaging with their community," Seif said.
But in Syria, as in Yemen, the news of Gaddafi's death could simply entrench both sides in confrontation, as leaders do all in their powers to avoid sharing his fate.
"It may give courage (to protesters) but it may also give the regime extra impetus to resist any opposition," said Nikolaos Van Dam, a Dutch scholar and former diplomat.
Pointing to the huge military advantage Assad's forces have over his opponents, despite the reported desertions of thousands of Sunni Muslim army conscripts, Van Dam said the impact of Gaddafi's death would be limited.
"The motivation may be stronger, but it doesn't mean success," he said.
Syrian television described the killing as an assassination and stressed the civilian deaths and bomb damage it said NATO had caused -- a repeated theme of state media seeking to show what Western powers might inflict on Syria.
"Most people in the West have thought only about toppling Gaddafi but they haven't thought about what happens afterwards," Van Dam said. "That is the point of the Syrian regime -- is it going to be better when the regime falls?"
(Additional reporting by Erika Solomon in Dubai; Editing by Myra MacDonald)