IT MIGHT have been a moment of hope: an internationally negotiated ceasefire that would lead to a political deal to end a war that has probably killed nearly half a million people and turned millions more into refugees. The accord was thrashed out by America and Russia on February 12th in the wings of the annual Munich Security Conference, endorsed by the 17-nation International Syria Support Group—a cruel misnomer if ever there was one. Its chances of success were never good.

Humanitarian aid to besieged towns was supposed to be the first part of the deal, followed by a “cessation of hostilities” within a week. There are some signs of the former—the UN announced an agreement with the regime on February 16th for access to seven towns, perhaps including air-drops into Deir al-Zor, a city largely held by Islamic State (IS). On February 17th some aid convoys began to roll out of Damascus. But there remains virtually no prospect of a ceasefire.

Nobody should be surprised, given the cheerful assertion by Sergei Lavrov, Russian’s foreign minister, that, despite signing the agreement, Russia would continue its air strikes against those it regards as “terrorists”. That is an elastic term. Jabhat al-Nusra (JAN), al-Qaeda’s powerful Syrian arm, fights alongside many other forces, both jihadist outfits and less extreme ones supported by the West, so Russia feels justified in bombing just about any rebels it chooses.

Since Russia’s intervention at the end of September, supposedly to attack IS and JAN, the dynamics on the ground have been transformed. Once close to collapse, the regime of Bashar al-Assad is now confident of its survival and intent on regaining control of more territory. Pro-Assad forces are encircling the rebel-held parts of Aleppo, once Syria’s biggest city. Why should he and Mr Putin stop now?

The only puzzle is what John Kerry, America’s secretary of state, thought he could achieve through his agreement with Mr Lavrov—except, perhaps, to expose Russian cynicism. As John McCain, the chairman of the Senate armed services committee, put it: “This is diplomacy in the service of military aggression. And it is working because we are letting it.”

In the few days since the Munich agreement, the war has, if anything, widened and intensified. On February 15th nearly 50 civilians were killed when missiles hit rebel-held areas of Syria. At least 14 were killed in the northern town of Azaz when missiles hit two hospitals and a school where refugees were sheltering. Missiles also struck a hospital in Marat Numan, in Idlib province, south of Aleppo (see map). In all, five medical facilities were targeted. The UN condemned the attacks as a violation of international law. Turkey’s foreign ministry accused Russia of “an obvious war crime”.

The animosity between Moscow and Ankara is further fuelled by the advance of the Syrian Democratic Forces (SDF), an alliance of Kurdish and Arab fighters under the umbrella of the PYD, the main Syrian Kurdish force. This had been America’s most reliable ally on the ground against IS. But now, aided by Russian planes and weapons deliveries, it is fighting in tacit alliance with Mr Assad’s regime. On February 2nd the SDF severed the corridor between Aleppo and the Turkish border that is critical for rebel supplies. On February 15th it seized control of Tel Rifaat, one of the first towns to rise up against Mr Assad, squeezing the “Azaz pocket”, a rebel bastion on the border with Turkey.

The rush to Rojava

The Kurds want to carve out a continuous autonomous area by linking up the two enclaves they control along Syria’s border with Turkey. In the recently opened PYD office in Moscow, there is a map of a future Syrian Kurdistan, called “Rojava”. It covers a lot of territory.

Turkey is determined to stop the Kurds and has been shelling them for the past week. Its prime minister, Ahmet Davutoglu, says that Turkey “will not let Azaz fall” and threatens a “severe response” if the Kurdish-led forces try to take the town.

Tens of thousands of refugees are flowing out of Aleppo, heading both north towards the Turkish border town, Kilis, and west into mainly rebel-held Idlib. The regime seems all too happy to let the city’s population flow out through its siege lines.

Noah Bonsey of the International Crisis Group, a think-tank, believes that there is nothing indiscriminate about the bombing of civilian areas and infrastructure, including schools and hospitals. Both Aleppo’s main hospitals were systematically destroyed by Russian air strikes last week. The aim is twofold: to terrify civilians into leaving, so that even more ruthless tactics can be used against the fighters who remain; and to raise the price of resistance to the point at which communities will put pressure on fighters to accept whatever ceasefire terms the regime is prepared to offer, as happened in Homs two months ago.

Western diplomats accuse Russia’s president, Vladimir Putin, of “weaponising” refugees to threaten Europe and punish Turkey, which supports the rebels and in November shot down a Russian plane that had crossed into its airspace. Turkey is doing everything it can to hold back the exodus from Aleppo by building big refugee camps on the Syrian side of the border. It is not yet clear whether it is prepared to defend these new camps against Russian or regime attacks. If it is, it could be the prelude to establishing an informal safe zone along the border—something the Turks have long demanded, but which America has refused to do, even when it would have been a lot less dangerous than it is now. Shooting down stray regime helicopters is one thing; risking a direct military confrontation with Russia is quite another. Syrian opposition leaders see it only slightly differently. One says: “It looks like Turkey is trying to create a humanitarian crisis. They think that maybe it could make the West finally act.”

In fact, there is little prospect of Western intervention. Even if Russia and Turkey come to blows in Syria it is not at all clear that NATO, of which Turkey is a member, would be obliged to come to its aid unless Turkey’s own territory were under attack. The desperate diplomatic floundering of Mr Kerry suggests that President Barack Obama, with only a year left in office, will not adopt a more hawkish approach unless events force him to.

In the absence of direct Western military intervention, most military analysts doubt that much can be done to stave off further rebel defeats. The Saudis are thinking of supplying them with shoulder-fired anti-aircraft missiles. But America rejects this idea because of the danger that they would be used by terrorists to shoot down passenger airliners around the world.

None of this means that Aleppo will fall quickly to regime forces. There are about 40,000 battle-hardened rebel fighters from more than 50 opposition groups still in the city. Most have remained relatively independent of JAN. As a recent analysis by the Institute for the Study of War, a think-tank in Washington, DC, argues, they are a resilient bunch. However, the think-tank warns that the pressure of the coming siege will be used by JAN and its Salafi-jihadist ally, Ahrar al-Sham, to get moderate groups, who feel betrayed by the West, to merge with them. That would play into the regime’s account of the opposition being composed only of “terrorists”.

Without Russian air support the pro-regime forces ranged against them would look a lot less formidable. There are relatively few units of the Alawite-led Syrian army left. By the middle of last year it was on the brink of disintegration. It is now being retrained and rearmed by the Russians, but it is largely deployed close to the regime’s heartland in Damascus and Latakia. Most of the forces around Aleppo are Iranian-led Shia militias, from Lebanon and Iraq, with some fighters from Afghanistan and Pakistan. Western intelligence sources put their number at about 15,000, not including around 5,000 from Hizbullah, the powerful Lebanese Shia militia. Some Russian Spetsnaz special forces are working on the ground, co-ordinating air strikes. One rebel commander said: “We can beat them on the battlefield. Our men have been fighting them for five years and this is their terrain. But the Russian bombings make the difference.”

The West agonises over its self-inflicted impotence, while Turkey and its Gulf allies flail and threaten. But Mr Putin has a clear strategy that appears to be succeeding on almost every level. A newly confident Mr Assad talks about retaking the country bit by ruined bit.

Vlad the victor

Mr Putin’s immediate aim is to return Aleppo to government hands, allow the Kurds to create at least a semi-autonomous region in the north and then to use the suspended UN-sponsored peace process to lock in these gains. Underpinning this plan is his belief that a European Union bickering about refugees is desperate for the war to end at almost any cost, while Mr Obama has already given up trying (not very hard) to get rid of Mr Assad.

As a juicy carrot, Mr Putin will hold out the promise of a genuinely concerted attack on IS in eastern Syria to bolster the apparently feeble efforts of Mr Obama’s coalition. He may get a deal; he may even be prepared to offer up Mr Assad as well, as long as he is replaced by someone Russia finds acceptable.

From a wider perspective, Mr Putin’s strategy is paying dividends. His overarching reason for sending bombers to Syria, so soon after annexing Crimea and stirring up a separatist war in east Ukraine, is to force the West to take Russia seriously as a great power. In both cases the Kremlin portrays its action merely as a response to the provocative behaviour of America and its allies. In Mr Putin’s mind the revolution in Kiev in February 2014 was the result of a Western plot to claw Ukraine away from Russia. Similarly, the war in Syria was fomented by the West with the aim of dislodging Mr Assad. It is now getting its comeuppance, he believes.

The flow of refugees into Europe, increased by Russian air strikes, is another bonus. Mr Putin has for several years been giving material support to populist and nativist parties in Europe that oppose the EU. They have been boosted by the union’s floundering response to the migrant crisis. A weakened EU, Mr Putin calculates, should make it easier to keep the likes of Ukraine, Georgia and Belarus within Russia’s sphere of influence.

Not least, the Syrian campaign is helping to maintain Mr Putin’s approval ratings at home, which remain steady at more than 80% despite a painful recession in Russia, caused by cheap oil, Western sanctions and Mr Putin’s own misgovernment. Russian television depicts the war as an action blockbuster to cheering viewers. After Russian bombs hit hospitals in Aleppo, it shifted the blame onto America by showing footage of US Air Force A-10s allegedly operating in the skies over the city. America’s weary denial only confirmed its guilt. According to the Levada Centre, a pollster, nearly 60% of Russians support the war in Syria.

Yet however successful Mr Putin’s strategy appears now, it is fraught with risk. Saudi Arabia, as the leader of a newly formed Islamic coalition, is conducting large-scale exercises, possibly in preparation for a ground campaign against IS. Turkey, to which the Saudis have recently sent planes, could become a partner. If they were to go ahead (and it remains a very big “if”), matters would be unlikely to stop there: regime forces could also come under attack, directly or indirectly. Russia would then either have to insert substantial ground forces of its own or back down, while America might have little option other than to support its allies.

At best Mr Putin will have to contend with an incomplete triumph. Even with the help of Russia, Iran and Shia mercenaries, Mr Assad can at most retake the populous western end of the country. He will continue to face a large, radicalised insurgency. Mr Putin may find it as difficult to withdraw from Syria as the West has from Afghanistan. Nor will his promise of working with America to defeat IS be honoured unless Sunni Arabs are prepared to take and hold IS’s stronghold in Raqqa and the surrounding area can be taken and held by Sunni Arabs—in other words, those Russia now describes as “terrorists”. Mr Putin and Mr Assad may feel like winners for now. But in Syria “winning” and “victory” are slippery terms.