Zabadani, a mountain town north-west of Damascus near the Lebanese border, was one of the first Syrian towns to be liberated from the Assad regime, in January 2012, and one of the first to establish a revolutionary council. It has been besieged and intermittently shelled since.

Since July 3, it has been subjected to a full-scale assault by Hizbollah, alongside continuous barrel bombing. It has been reported that the town’s 800-year-old Al Jisr mosque has been pulverised. Human losses are in the hundreds.

Elsewhere, ISIL has bulldozed the 1,500-year-old monastery of Mar Elian in Al Qaryatain and blown up the beautiful 2,000-year-old temple of Baalshamin in Palmyra. The people, monuments, even landscapes that Syrians once took for granted, that they assumed their grandchildren would enjoy, are disappearing forever.

Palmyra – Queen Zenobia’s desert city – is a world heritage site and perhaps Syria’s most precious cultural jewel. Remarkably intact until recently, it provided a tangible link to antiquity and a breathtaking proof of the region’s civilisational wealth. Nationalist Syrians, whether secular or religious, feel the importance of such sites for communal pride and identity. Rational Syrians can understand their benefit to any future tourism industry.

Neither Bashar Al Assad nor ISIL “caliph” Abu Bakr Al Baghdadi are nationalists. Mr Al Baghdadi is explicit about it: “Syria is not for the Syrians,” he says, “and Iraq is not for the Iraqis.” Mr Al Assad’s rhetoric is still nationalist (and sectarian), but his war effort is managed by a foreign power now pushing towards the nation’s partition. Though not nationalists, both are certainly fascists obsessed with reinforcing their respective totalitarian states and eliminating any independent intellectual influence. Thus, in a flesh-and-blood echo of its slaughter of Palmyran history, ISIL tortured and beheaded Palmyra’s head of antiquities, 81-year-old Khaled Al Assaad.

When ISIL destroys Baal’s temple, when the regime destroys the Zabadani mosque (or Aleppo’s Umawi mosque, or Deraa’s Omari mosque), it’s as if fascist forces have destroyed Stonehenge or the Tower of London. It declares a total rupture with the past.

Rebel groups have also assaulted Syria’s heritage, though on a smaller scale, either by looting sites to raise funds or by firing at them when the regime is ensconced within. With the possible exception of Al Qaeda-linked Jabhat Al Nusra, however, these groups at least want to preserve Syria’s territorial integrity.

Of course the borders are not sacrosanct. All borders are acts of the imagination, and the Sykes-Picot borders in the Middle East are more artificial than most. They were drawn by foreign imperialists – either clumsily or maliciously, according to your reading – and manifested an order in which minorities wielded power over majorities.

The dissolution of these false borders would be welcome if it implied a dissolution of repressive state structures (and foreign interference), and an empowerment of individuals and communities. It would be welcome if it ended the political exploitation of sect. But both the Assad regime and ISIL offer the opposite, and neither of their projects can provide stability. At once a perverse reincarnation of Baathist tyranny and a homeland for international fantasists, the ISIL state is a temporary phenomenon, a parasite feeding on Mr Al Assad’s war. And Mr Al Assad’s shrinking state is an Iranian puppet running low on Syrian manpower.

When negotiations were held over Zabadani, the militia Ahrar Al Sham spoke on behalf of the rebels. Its interlocutor was not the Syrian regime, but the Islamic Republic of Iran. Ahrar hoped to win a mutual ceasefire but it broke off talks when the Iranians demanded instead a population exchange – that Sunni residents leave Zabadani, and Shia residents leave Fu’ah and Kafraya.

Having failed to hold most of Syria, Mr Al Assad and the Iranians aim now to retrench in an area stretching from the coast through Homs along the Lebanese border to Damascus. This is their version of what the French occupiers called la Syrie utile (“useful Syria”). The sectarian cleansing of strategic zones in this area began in 2013 and continues with the current assault on Zabadani and the increased aerial bombardment of the Ghouta suburbs of Damascus. On August 16, barrel bombs killed over 100 people in a Douma marketplace.

It goes on day by day – Syria’s present, past and future dissolve, and the world participates in the tragedy. Britain reopens its embassy in Tehran. The UN sups with Mr Al Assad. The US, long retreated from its anti-regime threats, bombs moderate opposition groups like Jaish Al Sunna as well as ISIL. Worse, it seems the Americans are using their involvement in the multinational operations centre in Jordan to hold back the Free Army’s Southern Front from victory in Deraa.

Zabadani, teetering on the edge of defeat and cultural annihilation, still holds out at the time of writing, even counter-attacking Hizbollah checkpoints. This at least exists in the present.

Robin Yassin-Kassab is the author of The Road from Damascus