While Israel believes its war with Hezb'allah had reinvigorated its deterrence posture, an Iranian attack on Israel is now more likely than before. Two main reasons account for this forecast. First, Tehran must now realize that its strategy of relying on Hezb'allah as a stopgap deterrent to facilitate Iran's acquisition of nuclear weapons has been wrecked. Israel's forceful riposte indicated Hezb'allah's vast arsenal of rockets was for naught deterrence—wise. The anomalous theory that a terror organization could provide a strategic umbrella to its sponsor has been debunked.

Second, Tehran must be worried that in the war's wake, the likelihood of an Israeli preemptive attack has gone up. During the war, Israeli Prime Minister Ehud Olmert declared that Israel's robust reaction and the resilience of its rear under continued bombardment proved that the country was undeterable. The unmistakable implication was that Israel would revert to its once preferred preemptive strategy. Moreover, the war likely caused Israel to assess that the effort to prevent Iran from achieving nuclear weapons must be expedited. Not only was the country reminded of its vulnerability to missile attacks, but the wholesale targeting of their population centers convinced Israelis that when Iran's leaders speak of 'wiping Israel off the map,' they actually mean it. Indeed, the more is the war perceived by Israelis as a failure the greater the alarm over Iran and the higher the probability that Israel would act soon to redress the Middle Eastern power balance in its favor.

Although Israel refrained from attacking Syria or Iran during the war, despite repeated statements highlighting these countries' involvement with Hezb'allah, Tehran cannot assume this inaction is evidence of the effectiveness of its deterrence. It was in Israel's interest not to expand the conflict so long as the IDF was busy on two fronts—Lebanon and Gaza——and provided its fight against Hezb'allah proceeded without outside interference. Limiting the war geographically was also dictated by Jerusalem's quest to maintain international support.

In sum, Iran today must feel more exposed to an Israeli attack whose chances, it may well assess, have risen sharply. In this context the fact that the recent IDF entanglement in Lebanon was a brief one, and that its offensive received support from official Arab quarters cannot but arouse Tehran's anxiety. Under these circumstances what could Iran do?

First, it could seek to resupply Hezb'allah expeditiously so the latter can resume its deterrent posture. However, Israel is unlikely to tolerate the rearmament of the organization. The Lebanese public at large might be equally opposed to a new arms influx given the horrendous damage inflicted on Lebanon by  Hezb'allah's adventurism. Worse yet, the new buildup may be pointless given Hezb'allah's recent failure to deter the IDF.

Second, Iran is likely to increase efforts to divert Israel by stoking Palestinian terrorism. For example in early September Israeli security disclosed it has arrested two Palestinian operatives who were trying to launch rockets from the West Bank into central Israel with the backing of Hezb'allah. However, even if other such efforts were successful, the resulting escalation would only marginally affect Israel's ability to go after the Iranian nuclear program.

Third, Iran could evince flexibility in negotiations over its nuclear program. But with Tehran defying the U.N. Security Council deadline on stopping uranium enrichment, it is difficult to discern any Iranian give. In any case what transpires between Iran and the international community would only have a limited bearing on Israel's decisions unless there was tangible progress toward halting the nuclear program.

Fourth, Iran may accelerate its nuclear program. This would also be of limited usefulness given that the Iranian effort has probably been at full throttle for some time now. Even a crash program can only do so much to overcome the kind of technical hurdles the Iranian project is reportedly facing. Moreover, the lead—time until Iran can field an operational nuclear force is rather lengthy.

Fifth, Iran has already undertaken to beef up its military preparedness through extensive military exercises. By highly publicizing the maneuvers Tehran undoubtedly was seeking to enhance its deterrence against an attack.

Yet, Iran itself appears to question whether these measures would bolster its deterrent potential. The commander—in—chief of its armed forces, Gen. Atollah Salehi, for instance said the IDF 'has gone mad' in Lebanon. He went on to say:

"What we know about this enemy [Israel] up until now is that it is insane. Therefore we must always be prepared in the face of this insane enemy."

Iranian concerns were not allayed when Mr. Olmert, in early September, reportedly told the Knesset's Foreign Affairs and Defense Committee: 

"If we have go to war with Syria, we will do away the limitations on the use of force we placed upon ourselves in Lebanon."

Further, Iran's worst—case calculations might well assume that the U.S.
might assist an Israeli attack if not in fact take an active part itself.

The bottom line for Iran is that none of the above options, by themselves or in combination, represent an effective response to the geostrategic circumstances in which it finds itself in the aftermath of the war in Lebanon. As a result, a large—scale Iranian attack against Israel with Syria 's help is certainly not a wildly hypothetical possibility in the war's wake. While risky, Tehran may feel this option offers the best prospect of blunting the effects of a likely Israeli preemption.

In this context, the culmination of recent military exercises with the test firing of a one—ton guided flying bomb is telling. While the publicity accorded the test may indicate Iran deterrent motives, for instance by signaling its ability to hold the Dimona reactor hostage, the fact remains that Iran is developing the capacity to hit hardened targets. This could facilitate an attack on Israel, by seeking to surprise the IAF in its hangars or even preempting Israel's reported hardened storage sites of its nuclear warheads.

Avigdor Haselkorn is the author of The Continuing Storm: Iraq, Poisonous Weapons and Deterrence (Yale University Press)