Trump is breaking his promises - and that's good news for Ireland
The first large-scale use of chemical weapons took place in this month 102 years ago. Poison gas then came to be used frequently by all sides throughout the First World War. By the time that conflict ended in 1918, more than a million people had been killed or maimed by weaponised chemicals.
Despite their frequent use in that war, chemical weapons were rarely used again in conflicts. International agreements, signed in the wake of the slaughter in Europe, prevented their deployment in most wars. Only a handful of the most brutal regimes, including those of Adolf Hitler and Saddam Hussein, used them. Limiting the use of non-conventional weapons has been one of the real achievements of international society over the past 102 years.
Four years ago, Bashar Assad joined the tiny group of leaders over the past century to use chemical weapons. The Syrian president did so despite a warning he had been given by then US president Barack Obama. Washington flagged clearly that using the weapons would amount to the crossing of a red line. Mr Assad went ahead anyway. There was no US response.