* Iran is aggressively pursuing nuclear, biological, and chemical (NBC) weapons, ballistic missiles and other means of delivery and its use of NBC will be particularly difficult to deter. The possibility of deterrence failing is significant.
* Predictions that Iran shares the Western perspectives on NBC use or that it would employ NBC weapons strictly as weapons of last resort may be dangerously misleading. There are few apparent moral or religious impediments should Iranian leaders choose to employ NBC weapons.
* Iran considers the United States to be the primary threat to Iranian interests, and U.S. forces in the region could well be perceived by Iran as lucrative targets for NBC weapons--which Iran will be able to deliver through both traditional and novel means, presenting challenges to U.S. defenses. NBC use may be Iran's only means of offsetting U.S. technically and numerically superior forces.
* Threats of conventional force or even nuclear retaliation may pay only minimal returns toward deterrence.
* The United States needs to employ a combination of denial and jeopardy to achieve deterrence. Denial will require robust active and passive defenses and counterforce. Jeopardy requires developing the capability to credibly put at risk the two Iranian centers of gravity: the Iranian Revolutionary Guard Corps and Iran's oil revenues.
What Makes Iran Hard to Deter?
Iran more closely resembles the early Bolshevik state than the tired Soviet Union the United States deterred and defeated in the Cold War. Iran is a prime example of Eric Hoffer's "intensely frustrated" that make up the world's "true believers" with their high tolerance for risk. Iran thus presents a particular challenge to deterrence.
Like the early Bolshevik state, Iran has a self-appointed vanguard, the Iranian Revolutionary Guard Corps (IRGC). It has a centralized revolutionary purpose, including export of the Iranian Islamic revolution. The IRGC has the lead in Iran for the production and employment of NBC weapons and is well organized, coherent, and virulent in their hatred of the United States. IRGC leaders often believe that they are more religiously correct than some religious leaders or "mullahs" and there are instances in which the IRGC has taken radical action beyond that of the state's political leadership.
As the United States seeks to deter Iranian aggression in general, and its use of NBC weapons in particular, it is prudent to try to understand the legal and moral traditions that provide a context for Iranian decisions about war. Shiite tradition differs from Western "just war" tradition. While Iranian Shiite interpretations of Islam forbid declaration of offensive religious war, there is a standing authority and indeed an obligation to use force to defend Islam. Such use of force is not considered to be offensive since the persecution of believers is the same as an attack. A jihad (holy war) could thus be readily justified as "defensive." This might mistakenly lead some to believe that Iran would only fight 'defensively' in the sense that it would not strike first and would see NBC weapons strictly as weapons of last resort. However, as a practical matter, virtually any act contrary to Iran's interests taken by the West (such as the U.S. embargo) could be defined by the mullahs as "persecution." Further, while Western just war tradition obliges restraint in the prosecution of war, particularly the requirement that combatants limit, to the greatest degree possible, the impact on non-combatants, once a defensive jihad is declared against disbelievers, there need be little restraint in its prosecution. Employment of NBC weapons, even against civilians--let alone the military--could be justified. Thus there are few apparent moral or religious impediments should Iran choose to employ NBC weapons against the United States. Assessments which fail to recognize that the Iranian justification for war has a significantly lower threshold than that established by Western just war doctrine could be dangerously misleading. …