However, FDR on his way to Yalta, disapproved of the plan for political reasons. I guess dropping the A-bomb, or firebombing Dresden was OK, but using Poison Gas on Iwo would have made us look bad. Of course, FDR was sick man at this point, and died a couple months later.
we knew the germans had poison gas before ww2 started but they never used it because hitler feared retaliation. even as germany was collapsing they didn't use poison gas. if fdr had used it, it would have opened the door for the germans to use it.
this is a good article about decision making and, in no way, insults the courage of the men fighting there. when studying the past too many revisionists think in terms of 2001 morality instead of trying to understand the decisions in the times they were made.