Escalation

Several months ago, Philip Sabin appeared on a TV programme about Hannibal, discussing Carthage and Rome. More on him here: interview with... 

He made another contribution to the Efraim Karsh's book that I mentioned previously - 'Escalation in The Iran-Iraq War'. This seemed to me to be a very penetrating and succint analysis:

Likewise, the Iraqis used chemical weapons initially as a last resort device to forestall Iranian breakthroughs, a fact which may have made it harder for NATO nations to issue an uncompromising condemnation given their own dependence on escalation to nuclear strikes in such a circumstance.'

The initial use was at Majnoun in March 1984.  Chemical weapons were used in the final offensive in July 1988, after Iran had already agreed to the UN ceasefire.

'Just as one reason for President Sadat’s attack on Israel in 1973 was to shock the United States into doing something to settle the issue of the occupied territorrities, so a major reason why Saddam Hussein launched the ‘tanker war’ in 1984 was that he wished to provoke Iranian reprisals against the shipping of the Gulf states. This, he hoped, would either bring the united States into the war against Iran or would create sufficient international pressure to compel the ceasefire which Iraq desired.

Iran, the Gulf states and the USA itself were all understandably reluctant to fall in with this plan, but the Iranians were eventually provoked into sufficient reprisals to make Kuwait appeal for superpower protection. The Kuwaitis overcame US reluctance to be dragged in by playing on superpower rivalry and threatening to invite Soviet intervention instead. Fortunately, both superpowers had now gravitated against Iran for refusing to end this increasingly dangerous conflict, and direct US involvement did not go far before the combined pressues of the major powers impelled the antagonists to reach a ceasefire.