The most telling moment in the downfall of the Qaddafi regime came when the heir-apparent Saif Al Islam, on whom reformers had pinned their hopes, spoke on television as the revolution gathered pace. Speaking without notes in colloquial Arabic, he was defiant, promising that his father would never relinquish power. It was the moment when he could have broken with his father, but didn't.
The sins of the fathers have been propagated by the sons. Arab republics that were founded to replace decaying monarchies became stagnant and practically hereditary: in Libya, in Yemen, in Egypt, presidents plotted to pass power to their sons. In Syria, it happened.
Both Gamal Mubarak and Saif Al Islam had a lot more to lose than their fathers. Both are relatively young, still in their 40s; both enjoyed opulent, jet-setting lifestyles; and crucially both had international respectability and were welcomed in the business and political circles of the Arab world and the West. It is a long fall to the dock in The Hague or, in Mr Mubarak's case, a jail cell in Cairo.
Why, then, as the end became clear, did they not break with their fathers?
The question is more pertinent for Saif Al Islam and Bashar Al Assad because they had longer to consider the consequences. Gamal Mubarak had been brought up in a stagnant political landscape where, even until relatively late last year, he could have legitimately expected to inherit his father's regime. The speed with which Mubarak rule unravelled left little time to explore alternatives.
Saif Al Islam had no such uncertainty. Two leaders had been removed and two more (in Syria and Yemen) were tottering. Having seen the US fail to stop the Egyptian revolution, and then abandon Hosni Mubarak, he must have recognised that the Libyan leadership, with far fewer friends and a lesser role in the international order, was doomed. And yet he gave that remarkable speech promising to defend his father's regime.
Beyond filial affection, part of the reason lies in the nature of power and how it changed over the course of a generation. Both Muammar Qaddafi and Hafez Al Assad came to power in military coups and held power by focusing on security, creating huge networks of informers to guard against the very thing that had brought them to power.
Their sons came of political age under a very different system. The rule of their fathers had stabilised, or at least stifled, their respective countries. Both sons benefited from education and experiences in stable countries, which may have made them think the stability of their countries was real when it was merely apparent.
There was also an inability to grasp what was happening. Cloistered at the apex of the regime, surrounded by people who attained their positions and wealth by always saying yes, leaders were insulated from information that might have saved them.
But the biggest reason is that they could not break with the past and still survive.
For a scion of either the Qaddafis or the Assads to attempt a change in government would mean a fundamentally different political contract. Such a change would undermine the nature of the regime and erode its support base, effectively signalling its end.
Unlike monarchies, the legitimacy of the rulers did not stem from their lineage, but from a contract with their citizens, whereby the regime provided stability and security in return for acquiescence. Inherent in that system was the role of the ruler as a dispenser of political favours: the political order was not a reflection of the demands or aspirations of the people, but rather a system that had been given by the president and could be taken away.
That system persisted for a very long time, until the Arab uprisings. The difficulty that the Qaddafis had in the past, and Mr Al Assad has now, is that they cannot grasp that the political contract has fundamentally changed. Each leader of the Arab republics has suffered the same problem. Unable to deal with the change, they have tried to gift their way out of unrest. Every one of these leaders has gone before their people and tried to offer reforms as a form of largesse. Each failed, for the same reason: people understand that the political contract has changed. They are no longer negotiating from a position of weakness.
This suggests a possible way out for Mr Al Assad. He could, by reforming the political order, ensure his survival but on terms that would not end in a cell or a grave.
Why, then, does he not do it?
The answer is that, like each of these leaders' sons, he could not hope to challenge his father's legacy and remain in power. To unravel the political contract would so fundamentally undermine the regime that it would collapse.
Each dictator had built a matrix around himself and his coterie, a reality in which it made perfect sense to try to slaughter his way past unrest to preserve the regime. For Saif Al Islam in the past, and Mr Al Assad today, stepping outside that matrix would invite the destruction of the whole structure. The edifice that kept the regime safe is now a cage.
And that is why Mr Al Assad's fate seems inevitable. Locked in a matrix of his father's making, he is certain to repeat the sins of the past.