THE WORLD was shocked by this week's revelation that a 1,400-year-old monastery in Iraq had been razed to the ground by Islamic State (IS). Satellite pictures obtained and studied by Associated Press confirmed that the ancient edifice, which had withstood centuries of local conflict and natural decay, was now rubble. The final act of destruction at the monastery of Saint Elijah seems to have taken place in autumn 2014, soon after IS overran the area. Before that it was a semi-intact structure, with 26 rooms including a sanctuary and chapel, although the roof was missing. The Greek symbols Chi and Rho, the first two letters of the name of Christ, marked the entrance. The news was deplored not only by the Obama administration, the Vatican and UNESCO, but also by individuals who knew the place as a recent centre of worship. In pre-IS days, hundreds of Christians from the nearby city of Mosul were in the habit of making pilgrimages there, according to John Pontifex, a charity worker who has visited the area for Aid to the Church in Need, a Catholic relief agency. Monsignor Nezar Simaan, a leader of the Iraqi Catholic community in London, said the news would deepen the gloom among the Christians still living as displaced persons in the far north of Iraq, and increase the flow of emigration.

But the latest revelation about cultural vandalism raises broader questions about the way historical and spiritual monuments are treated in war zones. To make a convincing case against IS, Western governments need to demonstrate their own respect for vulnerable heritage.

Of course, IS makes a point of flouting all the accepted laws of war; that is one of its selling points in the eyes of its fanatical supporters. But among organised states and armies, the principle, at least, of respect for culturally important objects, even in the heat of war, has been increasingly well-accepted over the past 100 years. Most of the war-crimes courts that have been established in recent times have a remit to consider the destruction of cultural heritage; and in building a legal case that genocide has occurred, the wrecking or theft of precious artefacts would certainly be viewed as supporting evidence.

But neither in theory nor in practice has the record of Western states been perfect. The main international instrument for protecting cultural heritage in war-time is the Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict, signed in 1954. It was prompted by the destruction and looting of artistic treasures by the Nazis. But during the cold war, America held off from ratifying; the Pentagon did not want to restrict the actions of its commanders in an all-out conflict. President Bill Clinton sent the treaty to Senate in 1999, and it was ratified, with some reservations, only in 2008; the United States has yet to ratify the convention's supplementary protocols which narrow down the circumstances ("imperative military necessity") in which a commander's hand can be untied.

All this has a direct connection to the fate of cultural monuments in Iraq, including Saint Elijah's monastery. During the assault on Saddam Hussein's regime in 2003, the monastery was used by the Iraqi army, and then taken over by the Americans, in the course of which a severed tank turret was smashed into a wall. The American army turned the edifice into a base and soldiers daubed some graffiti on the walls, until a military chaplain realized the spiritual significance of the place and launched a project to preserve the monument and use it for religious services. The showpiece conservation project was its height in 2008 when the Senate approved the Hague treaty, partly in response to the terrible vandalism and looting which had occurred across Iraq, for example at Baghdad's great museum.

One lesson from this story is that as well as signing up to treaties, Western armies should be fostering a mindset of respect for cultural heritage; just as future officers are trained in the basics of military law, as it applies to the treatment of civilians or prisoners, they need to know what international norms apply to places of spiritual or historic importance. Only a few armies take that matter seriously now. In the case of Saint Elijah's, it seems that only a lucky piece of vigilance by a chaplain gave the place a few extra years of life.

And there is one significant military power, with forces deployed in many of world's hot spots, which has yet to ratify the Hague convention, although the government says it will happen very soon. That is Britain.