The alleged use of chemical weapons against its own people by the Syrian government of Bashar Al Assad needs to be investigated. It is not enough that a White House spokesman says that Sarin gas is “likely to have been used on a small scale”. It is not enough that reporters interview the victims of the alleged attack and the doctors treating them.

The United Nations is the only body that has the authority and global standing to investigate such a claim. It is important that all nations recognise that the US does not have the credibility to make this judgment, since everybody remembers former secretary of state Colin Powell delivering his dossier on Iraq’s supposed weapons of mass destruction to the UN Security Council. He spoke seriously, but after the invasion not a single weapon was found.

If Al Assad has used such weapons, then he and his regime have to be called to account and he should be taken to the International Criminal Court to answer what will be charges of war crimes. Many will want to try Al Assad for the current war in Syria, but taking part in a war, however ghastly and murderous, is not a war crime. The current level of violence in Syria is seen to be different from using chemical and other weapons of mass destruction, which would be a war crime, as would be genocide.

US President Barack Obama warned Al Assad on Friday that any use of chemical weapons in Syria’s civil war would be a “game changer”, but at least Obama had the good sense to add that the intelligence assessments of the use of such weapons were still preliminary. The war in Syria is deeply destructive for Syria, but the way forward to a peaceful solution has to be found through rational process and inclusive dialogue. The people of Syria deserve a stable future governed by the rule of law. Therefore due process is required to investigate these terrible claims.