Commanders are eviscerated by air strikes; cities are recaptured one by one. Two years after its lightning advance along the Tigris and Euphrates valleys, the stench of decay hangs over the Islamic State of Iraq and the Levant (Isil).
The latest blow was the death of the movement's deputy leader, Taha Falaha - better known by his nom de guerre Abu Mohammed al-Adnani - who had incited Muslims in the West to "kill a disbelieving American or European, especially the spiteful and filthy French". At the moment he met his end - apparently by means of a US air strike - Adnani was Isil's chief dispatcher of terrorists into Europe and "governor" of its territory in Syria.
To grasp the attrition rate of Isil leaders, consider the fate of the previous holders of the latter position. One "governor" of Isil's Syrian domain was killed on March 3. His successor survived for less than a month before he too was eliminated on March 30. Adnani then stepped into the breach, lasting four and a bit months before meeting the business end of a missile.
Meanwhile, slowly but inexorably, Isil's self-proclaimed "caliphate" is being taken apart. Since the peak of its advance in 2014, the movement has lost about half of its territory in Iraq and a fifth in Syria.
So does this mean that Isil's final defeat is only a matter of time? Will there come a moment when a metaphorical white flag appears over its former realm? Not quite.
The first point to address is what "defeating" the "caliphate" would actually mean. If beating Isil means breaking its grip on territory, then that is perfectly achievable. The forces opposing Isil have proved their ability to recapture cities and overrun front lines, especially with the aid of US and coalition air strikes.
A long, bloody struggle lies ahead, but Isil's stranglehold on large areas of Syria and Iraq will eventually be broken. The next target will be the Iraqi city of Mosul, the largest population centre in Isil's hands and the place where Abu Bakr al-Baghdadi proclaimed himself "caliph" of an "Islamic State" in 2014. Already, Iraqi forces advancing up the Tigris are massing for an assault on Mosul.
Once that happens, the final domino to fall will be Raqqa, Isil's capital in eastern Syria. The recovery of these cities would mean Isil ceases to rule a large expanse of territory.
But there is one hard reality: the loss of territory would not amount to final defeat. Isil would respond by straining every sinew to carry out terrorist attacks, targeting Syria and Iraq, to be sure, but also Europe. Deprived of a realm to govern or a population to control, Isil would revert to being a purely terrorist organisation.
Much would also depend on who exactly recaptures Mosul, Raqqa and the rest of Isil's domain. This brings us to the most important point of all. The emergence of this bloodstained movement was not some atavistic freak of nature. Isil is only a symptom of a deeply-rooted political problem, namely the exclusion from power of the Sunni minority in Iraq - and, even worse, of the Sunni majority in Syria.
By intervening in Iraq, the West paved the way for a Shia-dominated government to be elected in Baghdad. By not intervening in Syria, the West left Bashar al-Assad's minority Alawite regime in power in Damascus. The effect was the same, namely to reinforce the alienation of five million Sunnis in Iraq and 14 million in Syria.
There are, of course, plenty of Arab Sunnis who bitterly oppose Isil. But, so far, the biggest defeats suffered by the movement in Iraq have been inflicted not by the national army but by Shia militias, often taking their weapons and orders from Iran. In Syria, Kurdish guerrillas have emerged as the most effective force against Isil.
Yet Raqqa and Mosul are both inhabited largely by Sunni Arabs. Neither city may welcome "liberation" by Shias or Kurds. Hence the importance of ensuring that Mosul falls to Iraq's national army - and that Sunni Arabs lead whatever force eventually takes Raqqa. The difficulty of assembling this contingent, incidentally, is the main factor delaying the final battle for Raqqa.
The worst outcome of all would be for Raqqa to fall to Bashar al-Assad, whose regime, soaked in Sunni blood, relies on Shia and Alawite forces mobilised by Iran. It was Assad's relentless campaign to subdue Syria's Sunni majority which was the main factor behind the rise of Isil.
Eager to force the West and his own people to choose between him or the jihadists, Assad helped to engineer Isil's ascendancy. The most dangerous Islamists were released from his prisons, many going on to become Isil commanders. Assad filled the terrorist movement's coffers by buying its oil, while aiding its advance by focusing his military campaign against every other rebel group.
Kept in power by foreign bayonets against the furious opposition of millions of Syrians, Assad remains the great radicaliser of Sunnis.
If the aim is to defeat terrorism in the Levant, then Isil's downfall will not be enough. What is needed is a political settlement that includes the Sunnis of Syria. And that cannot happen while Assad reigns in Damascus.