In response to Iraq's use of chemical weapons during the Iran-Iraq War, Iran developed a modest CW capability and often warned that it would retaliate in kind. Whether it did so remains unclear.

The history of Iran's chemical weapons program, however, offers a number of important insights into how the regime thinks about the development and use of weapons of mass destruction, and the value system and strategic culture of the Islamic Republic's senior leadership. It thus provides vital context for the current debate regarding Iran's nuclear program.

The parallels between Iran's CW and nuclear programs are striking. In both cases, Iran claimed that religious rulings prevented it from developing WMD, though in neither case did these religious prohibitions prevent it from conducting weapons development work or from actually developing a CW capability.

Moreover, although Iran developed CW production capability, officials claim it did not weaponize the agent that it produced–perhaps in the hope that this would deter further Iraqi CW attacks, without the risk or opprobrium that weaponization or use would entail. This raises the question of whether a "nonweaponized" CW deterrent (if that is actually what it had) might serve as a template for a "recessed" or "nonweaponized" Iranian nuclear deterrent posture.

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See full text at the Washington Institute for Near East Policy: What Iran's Chemical Past Tells Us About Its Nuclear Future