AFTER swinging between reform and repression, President Bashar Assad has cracked down on anti-government protesters with renewed and desperate vigour. On April 22nd more than a hundred Syrians were killed in at least 14 different towns, by most counts bringing the death toll since demonstrations began in earnest a month ago to more than 450. On April 25th the repression reached a new ferocity when tanks rolled in to the southern city of Deraa, where the protests had begun. The death tally could yet rise sharply, as Mr Assad's legitimacy falls fast.

Before the army launched its attack on Deraa, electricity and communications were cut off and outsiders banned from entering. Water and bread have been running low. Wounded protesters are being denied access to medical treatment. Scores of people there and in other areas, including Douma, a suburb of the capital, Damascus, have been locked up. Checkpoints have proliferated. Parts of the country feel as if they are under siege.

After lifting the emergency laws that had prevailed in Syria for nearly half a century, Mr Assad seems to have run out of concessions to offer the protesters, who are demanding more vociferously than ever that he and his regime should go. But Mr Assad may think he can copy the methods that kept his father, Hafez, in power for 30 years until his death in 2000. When Islamists revolted in 1982 in the town of Hama, it is generally reckoned that the senior Assad, ordering his army to shell the place, left 20,000 people dead. Today's president has also shown he can be tough: when suppressing a Kurdish uprising in Syria's north-east in 2004, 30 were killed. But now he looks set to kill a lot more.

Mr Assad is still banking on the loyalty of his armed forces and police. Assorted paid thugs have been given batons and electric tasers. In the coastal towns, such as Latakia, a smuggling gang known as the Shabiha, linked through the minority Alawite religious group to the Assad clan, have carried out drive-by shootings of demonstrators. The army is run by hand-picked Alawites and Sunni loyalists. The ubiquitous Mukhabarat, or secret police, is likewise packed with placemen.

The security service, thought to number at least 65,000 full-timers, has been responsible for most of the violence. Set up by Hafez Assad soon after his coup in 1970, its 15-odd branches fall under four main intelligence headings: general, political, military and air force. Only tenuously linked to any civilian institution, they are above the law and sign off on virtually all big decisions. Their heads report directly to Mr Assad. “They provide security for the regime, not for the state,” explains a well-informed local. “They will never defect.” They also spy on each other. On occasions during the current crackdown their members have arrested or shot people from rival branches.

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If Mr Assad is confident of his ubiquitous security service, he must be worried by reports that some soldiers, probably conscripts, have been shot for refusing to fire on protesters. Some say that military units in Deraa actually turned against each other. But a large-scale defection is unlikely. Many officers hail from the Assads' own Alawite branch of Shia Islam and from other minorities, all owing a special allegiance to the regime. For the sake of appearances, the defence minister has usually been a Sunni. But in 2009 Ali Habib Mahmoud became the first Alawite in years to hold the post.

In the past mistrust has been felt between the Presidential Guard and the army's fourth division. Both are now believed to answer to Maher Assad, the president's powerful younger brother. The fourth division is considered akin to a private militia. Many of its officers are the sons of veterans once loyal to Hafez Assad's younger brother, Rifaat, who commanded the forces responsible for pulverising Hama in 1982 and who now lives in exile.

Although all the main levers of power are held by a group of Alawites close (and often related) to the Assad family, it is less clear whether the president himself is fully in charge. Some say Maher really calls the shots behind the scenes. There are frequent reports of angry debate inside the ruling circle between those who want reform and those who want to stick to the old system. The president has often been portrayed as a reformer who is less inclined to use force.

But he has proved capable of ruthlessness. After a big-shot former vice-president, Abdel Halim Khaddam, defected in 2005 and set himself up in opposition in Paris, Mr Assad spring-cleaned his regime. He sacked or switched round a number of senior security men and dumped his vice-presidents. After the assassination in Beirut in 2005 of Rafik Hariri, a tycoon who was five times prime minister of Lebanon, many blamed Mr Assad—or at least people close to him. Soon after that episode, Ghazi Kanaan, a former Syrian interior minister who for many years ran Syria's intelligence service in Lebanon, committed suicide in unexplained circumstances.

In any event, the inner circle today includes Maher Assad; Assef Shawkat, a brother-in-law of the president, who was formerly head of military intelligence and is now the army's deputy chief of staff; and Rami Makhlouf, a cousin of the president who is by far Syria's richest businessman. Behind this family troika is a clutch of extremely rich tycoons known as the “sons of power”, who are mostly from families of military men who were close to Hafez Assad. They hold sway in oil, gas, tourism and telecoms. A son of a former intelligence chief, Bahjat Suleiman, is a media mogul; the sugar monopoly is held by the son of Mustafa Tlass, a former long-serving defence minister. The current president has, until recently, been a lot more popular than the family troika and its business friends among ordinary Syrians.

Jumping ship

But the regime is not only Alawite. Mr Assad also depends on the loyalty of Sunni merchants in Damascus and Aleppo, Syria's second city, and of various Druze and Christians in high positions. There are signs that this wider coalition may be fraying. At least two members of the rubber-stamp parliament, a tribal sheikh and several figures from the ruling Baath party in Deraa, have recently defected. On April 27th it was reported that 200 members of the Baath party, most of them from Deraa, had left it. Some predict that Farouk Sharaa, the vice-president who comes from Deraa, may break with the regime.

The Assads' power-base, though founded on the Alawites, has expanded. “The regime was Alawi at the start,” says a senior diplomat, “but it strengthened itself by buying the support of a large part of the rest of the population. If they decide they have nothing to lose, this ploy could now turn out to be a weakness.”

Moreover, there are signs of division within the Alawite community itself. Along the coast near Latakia and in the hills above, fancy villas testify to the wealth of prominent Alawites. But the secretive community is divided into sects and tribes, some of which have done a lot better than others. The lower ranks have been catching the blame for the iniquities of Alawite rule, but none of the benefits. Several Alawites have recently criticised the regime; others have been arrested.

In any event, the regime has long relied on divide-and-rule tactics. Provincial governors are posted to towns other than their own; army conscripts tend to serve in areas with which they are unfamiliar. Posters have been appearing on walls, warning ominously against fitna, an Arabic word for division that has sectarian overtones.

But the biggest fissure, and a chief cause of the unrest now roiling the country, is between haves and have-nots rather than religious or ethnic groups. A popular chant among the protesters is “One! One! One! Syrians are one!” Most Syrians are practising Muslims, but the young people who have predominated in the crowds of protesters are connected to their compatriots more by the internet than by religion.

“Fears of sectarian strife are massively overblown,” says Rime Allaf, an expert on Syria at Chatham House, a foreign-policy think-tank in London. “No one is claiming all the sects love each other but there is no history of sectarian strife in Syria and little appetite for it now.” A good three-quarters of Syrians are Sunni, whereas around a tenth are Alawites and a tenth Christian.

A bigger problem for the opposition is that it has no obvious coherence or leadership. Political parties have been illegal. Syrians who have started civil groups have often been jailed. In 2001, after a brief breathing space following Hafez Assad's death known as the Damascus Spring, the new president clamped down on dissent. In 2005 there was another flurry of debate, as some well-known dissidents were freed, but once again it was short-lived.

The exiled opposition, including Mr Khaddam in Paris, the Islamist Movement for Justice and Development in London, and the Reform Party of Farid Ghadry in Washington, has never taken off. But inside Syria some of the signatories of the Damascus Declaration, an alliance of secular Syrians, Kurds and Islamists who got together in 2005, have been speaking out and are better known. More than 150 people have signed a new “national initiative for democratic change”.

Some of them are previous signatories of the Damascus Declaration. They include secular people, Islamists, Kurds and young campaigners who have recently emerged from the street in cities all over Syria. A network of young campaigners, including prominent women, such as Suheir Atassi, have been pushed into taking more overtly political role. Young writers and human-rights activists who have lobbied for causes such as Iraqi refugees have come to the fore. Riad Turk, a Sunni businessman who spent 25 years in jail, is a widely respected supporter. For the first time in years, the protests have been giving Syrians a chance to discuss the future outside the clamps of the Baath party. They all agree that one-party rule should end.

The Muslim Brotherhood, membership of which still carries the death penalty, would certainly benefit from Mr Assad's fall. But its exiled leaders, as elsewhere in the Middle East, are at pains to promote a non-violent vision. Muhammad Riad Shaqfa, the Syrian Brothers' London-based leader, says he does not want an Islamist state. But Syria's Islamists vary. The Sunnis vary too. Most of them shun political Islam. Radical Sunni parties had to remain underground. But most observers doubt they would be very popular if allowed to be legal.

Whereas the United States and European governments have castigated the Syrian government for shooting protesters, virtually all Arab governments in the vicinity have been silent, fearing a sectarian spillover if the strife were to worsen and spread. Turkey, which shares a border of 900km (560 miles) with Syria and dreads an influx of refugees, especially Kurds, has been the odd neighbour out. Its government has enjoyed good relations with Syria's for the past few years. But Turkey's prime minister, Recep Tayyip Erdogan, has publicly urged Mr Assad to use “maximum self-restraint” in dealing with the protests. It seems unlikely that Mr Assad will heed his words. But, even if he kills a lot more protesters, the momentum is against him.