The worrying lessons of the latest Syria atrocity

Evidence suggests Assad was behind this week’s chemical weapons attack. Leaders are saying it is a redline issue but Western powers are at a loss to respond, says Peter Apps

In terms of raw casualty numbers, Tuesday’s apparent nerve gas attack near the Syrian city of Khan Sheikhoun – believed to have killed at least 70 – should hardly be significant against the backdrop of a war that has left hundreds of thousands of people dead.

But that was never the point of chemical weapons. Since European powers first used them more than a century ago at the height of World War One, they have held a psychological and political shock value in many ways out of proportion to their physical or military effect. Alongside the threat of biological warfare, they hold a very distinct horror.