Like architecture and art, the value of some international agreements lies in the eye of the beholder. But no-one would seriously question the worth of the global ban on chemical weapons.
Today 192 countries have put aside their other differences and chosen to be parties to the Chemical Weapons Convention (CWC), which prohibits the production, use and stockpiling of these horrifying instruments of death.
We may find it impossible to abolish war, but we can at least agree to spare humanity from the unspeakable effects of these munitions.
This universal consensus on the moral abhorrence of chemical weapons reflects the tragic experience of many countries. Chemical weapons were used in France and Belgium during the First World War; they inflicted appalling suffering in Morocco in the 1920s, Ethiopia in the 1930s, China in the 1940s and Iran and Iraq in the 1980s.
This litany – by no means complete – was supposed to come to an end, once and for all, when the CWC entered into force in 1997. Yet since then, chemical weapons have been employed all over again in Syria and Iraq. A nerve agent was used to carry out an assassination at Kuala Lumpur international airport in Malaysia in 2017. Another category of nerve agent was employed in the British cathedral city of Salisbury in March.
It would be idle to pretend that these outrages make no difference to the integrity of the CWC. They all represent breaches of the global prohibition on chemical weapons that every country wishes to preserve.
Hence the need for a special session of the Conference of State Parties to the CWC that will take place in The Hague on 26 and 27 June. The aim is to reinforce the international ban and strengthen the Organisation for the Prohibition of Chemical Weapons (OPCW), which serves as the implementing arm of the Convention.
At the moment, the OPCW does not have a mandate to say who carried out chemical weapon attacks in Syria. Its experts can report what happened when and where, but they do not identify the perpetrator.
The international community lost that ability last November when the Security Council failed to renew the mandate of a Joint Investigative Mechanism comprised of the OPCW and the United Nations. This body had previously attributed four chemical weapon attacks to the Asad regime in Syria and two to Daesh.
Since then, the OPCW has found that chemical weapons were employed in Syria in Lataminah (March 2017) and Saraqib (February 2018). But the crucial question of who was responsible has been left unanswered.
How are we to preserve what we all believed was a universal taboo on the use of chemical weapons if the OPCW does not identify the offenders? The present situation indulges a fiction that chemical weapons descend from the sky of their own volition, without any agent or perpetrator.
If this anomaly is allowed to persist then any state or terrorist might use chemical weapons, safe in the knowledge that the OPCW will not identify them. The danger is that the taboo will transfer from employing these munitions to naming those responsible.
The best response would be to make full use of the provisions already in the CWC, which allow the OPCW to say not just whether chemical weapons were used but by whom.
I hope that the special session will give the OPCW a mandate to develop new proposals on how to identify any breaches of the Convention.
This is not a question of taking sides in some global confrontation; rather this is a simple choice over whether to uphold the prohibition on a terrible category of weapon or allow this ban to fade into irrelevance, posing a grave and growing risk to every country.
If we allow the use of chemical weapons to be normalised, they will not be confined to distant battlefields. What happened in Salisbury or Kuala Lumpur international airport could have happened anywhere.
We all share an interest in preserving and enforcing a prohibition on which our safety depends. And we cannot do that unless the OPCW is allowed to name an offender.