On 9 April 2003, in Firdos Square, Baghdad, US marines hauled down a giant statue of the recently toppled Iraqi dictator Saddam Hussein. The moment the metal figure hit the ground, it was immediately set upon by a crowd of civilians, who beat it with the soles of their shoes. Now the images of other Baathist dictators are coming down all over Syria. The Assad family knew from their experience of the Arab Spring of 2011 what can happen to dictators who fall into the hands of their own people. It appears that Bashar al-Assad may have fled at the last minute to Moscow.

The Assad regime had withstood 13 years of popular insurrection (at the cost of the deaths of over half a million Syrians), but its collapse came in as many days. The regime had been a highly personalised, relatively stable, dictatorship, which had brutally repressed opposition many times and survived. Bashar’s father, Hafez, crushed a rebellion of the Muslim Brotherhood in 1982, during which 20,000 lives were lost and the city of Hama obliterated. Today Hama is in rebel hands.

Why do dictators fall? Tyrannies are surprising institutions. Most authoritarian regimes are highly unstable, lasting in many cases no more than a year. Yet the Assads had held a continuous grip on power in Syria since 1971, which makes their tyranny one of the more successful. The Syrian dictatorship was, in fact, fairly typical of regimes where the leader has been allowed to gain a personal hold over the levers of power and so entrench his tyranny. Such despotisms are harder to dislodge. The Assad collapse has become yet another one of those surprises of history, in which a seemingly stable and functioning edifice of corruption and brutality gives way, all of a sudden, like a frozen cascade in spring.

It is this combination of apparent stability over time, combined with brief moments of terrifying vulnerability, that makes personal dictatorships so confusing – and so fascinating. What explains this strange situation?

Let us dispel one major mistake when dealing with dictatorships. These regimes do not have popular support. This should seem obvious: dictators do not hold free and fair elections, because they cannot be certain they will win. This explains the strength of dictators: they are not hostages to fortune. They do not lose elections or risk court cases. The system provides apparent certainty and security. Muammar Gaddafi, by 2011, had outlived Ronald Reagan, who had tried to kill him, and seen six other US presidents come and go. He fondly expected to survive the Obama administration as well, yet was disappointed.

Many commentators believe, nevertheless, that dictators maintain their grip on power by means of populist policies. How else to explain, first, the genuine fanaticism of core regime loyalists; second, the total absence of any criticism of the regime, but continual expressions of love for the dictator; and, third, following the fall of dictatorships, polls in countries as diverse as East Germany and the Dominican Republic that suggest widespread feelings of nostalgia for former authoritarian regimes. Is this not popular support?

In a word, no. Dictatorships do not attempt to persuade existing interest groups with a popular programme. Rather, they attempt to create a new interest group: the people of the dictator. This is always a narrow minority, ranging from two to 20 per cent of the population, characterised especially by party membership, employment in the security services or the possession of state sinecures. The Arabic term for this class is Ahl al-Thiqa, literally ‘people of trust’.

The power of dictators lies in their ability to offer patronage. They control the army – if they do control it – because they personally control military promotions. Corruption abounds as public offices become licenses to steal state assets. In countries such as Iraq and Libya, as well as many of the most brutal African dictatorships, this largesse is paid for by theft of natural resources, such as oil, diamonds and copper.

Patronage binds the inner circle of any dictatorship to the regime. Advancement in a tyrannical society involves graft. More broadly, any form of public service becomes a personal gift from the dictator to his people. In the process, a wide section of society is made complicit in the crimes and abuses of the regime. In extreme cases, where patronage is not available, even hunger can be used effectively as a weapon of control, as is currently the case in Venezuela. Non-cooperation with the regime can involve loss of access to food, which in North Korea in the 1990s, and perhaps even today, meant starvation. The best people, in such circumstances, die first. Guilt may explain to some extent nostalgia for authoritarianism: in order to denounce the dictatorship many would have to accept their part in maintaining the regime, a reckoning that some will not be prepared to face.

There are no ‘moderates’ in dictatorships. Such a term as ‘moderate’ or ‘liberal’ implies that members of the regime are in a position to consider the moral and practical benefits of distinct policies and choose rationally between them. This is not the case. There are many factions, and much debate, in dictatorships, but what determines these factions is relative proximity to the leader and the ability of elites to best position themselves to survive and thrive.

In reality, there are only three types within a dictatorship: the people of the dictator, who want to live well; the people on the street, who want to survive; and the enemies of the dictator, who are prepared to die. To become a dissident, an enemy of a dictator, requires not simply great courage, but also a gradual process of transformation similar in some ways to religious conversion. They have not only to recognise the evil of the regime, which is evident, but also prepare themselves to take the frightening consequences that come from such a recognition. Few will be willing to do so. Dictatorships in fact only ‘brainwash’ a small proportion of the population, if any at all. Most citizens will effectively ‘brainwash’ themselves and accept the propaganda because not doing so is too awful.

The old type of totalitarian and ideological dictatorships, known from the 20th century, are in decline. In their place are now openly rapacious personalist tyrannies, which have one explicit aim: the exploitation of the resources of the state for the benefit of tyrant and entourage. These dictatorships are new, but they are also at the same time a very old form of government, that would be recognisable as tyrannies to Plato and Aristotle. While they seem primitive, they are remarkably effective at dominating and manipulating human beings.

Why then do they suddenly collapse? Quite simply, they run out of money for corruption. Eventually there will be no assets to strip. Sudden drops in commodity prices become existential crises for dictators. Small regimes can get around this problem by accepting, then stealing, foreign aid. It is not just China, with its Belt and Road initiative, that is propping up dictatorships: the United States government has also done so, from Haiti, to the Congo, to the Philippines. Taxpayers in democracies need to question more vocally whether this money is well spent.

Even more important, though, is the human desire to be free, which remains unconquered, even if suppressed. This is not the same as a coherent aspiration for democracy. Many dissidents, especially among the Islamist groups that now occupy Damascus, do not want democracy. Another caveat is that the desire to be free is not enough to ensure peaceful or successful democratic transition. The slaves of 18th-century Saint-Domingue aspired to live in a free republic when they rebelled against their French masters. Yet today, their country, Haiti, is still one of the most violent and corrupt places on earth. The desire for freedom for oneself is not incompatible with the desire to enslave others. Syria is not free yet.

The Syrian war is part of a global conflict between tyrants and their slaves, the great struggle of our time. Everywhere, from Cuba to Kyiv, Belarus to Burma, tyrannised peoples are fighting their oppressors as and when they can. The West, distracted by toxic identity politics, barely seems to notice this battle. The new tyrants of our era are continually at war with their own peoples, whether openly or covertly, and continually focused on winning this eternal struggle. Other than self-enrichment, it is all they do and the only thing they do well; they do it extremely well. But they cannot always win. If allies disappear or turn off the funding, if oil prices go down, if food prices go up, then they may end up, as Assad has done, on a plane to the next dictatorship still standing.