Today's Observer has an interesting piece pointing out that at the time Saddam was using poison gas, both against Iranian troops, and Kurdish oppenenys, and killimng thousands of civilians inthe priocess, he was actually having his back protected bythe US. He was seen as the good guy in the war he started against Iran, and a few atrocities like thta weren't seen as too significant:

As Iraq's use of poison gases in war and in peace was public knowledge, the question arises: what did the United States administration do about it then?

Absolutely nothing. Indeed, so powerful was the grip of the pro-Baghdad lobby on the administration of Republican President Ronald Reagan that it got the White House to foil the Senate's attempt to penalise Iraq for its violation of the Geneva Protocol on Chemical Weapons to which it was a signatory.

This made Saddam believe that the US was his firm ally - a deduction that paved the way for his brutal invasion and occupation of Kuwait and the 1991 Gulf war, the outcomes of which have not yet fully played themselves out.