Anyone listening to recent statements made by cabinet ministers, the chief of staff, the head of Military Intelligence, the general in charge of Southern Command and others has heard them all refer to Israel's supposed ability to take independent deterrent action.

The prevalent assumption is that the Second Lebanon War, the bombing of the nuclear facility in Syria and Operation Cast Lead have greatly strengthened Israeli deterrence. The proof is the present quiet on the borders.

But then, almost in the same breath and without explaining the inherent contradiction, they all say this quiet won't last forever. The conclusion: Israel must prepare energetically for the possibility of a military or terrorist outbreak, and even thwart it with a preventive strike.

The calls for such an offensive primarily refer, of course, to Iran. It is not clear whether Israel really intends to attack Iran's nuclear facilities, or whether the speakers' sole aim is to strengthen the status of the defense establishment and increase its budget. But the government must deal with the contradiction in these statements.

To understand the situation, one must first understand one of the most basic elements of deterrence in inter-state conflicts and conflicts between states and groups referred to as terror organizations. Each of these conflicts involves two sides. A conflict cannot be one-sided. This sounds like a self-evident truth, but the overwhelming majority of the Israeli public, as well as politicians and military officials, act as though the Arab-Iranian side is the sole cause of the continued conflict and the inability to resolve it through negotiation.

The truth, of course, is that Israel has contributed and is contributing to the conflict to a large extent. The bilateral nature of the conflict means that the Arab-Iranian side is also trying incessantly to improve its deterrence vis-a-vis Israel and its ability to attack Israel. This is one of the main reasons Hezbollah continues to arm itself, Hamas continues smuggling arms to Gaza, and Iran insists on developing its nuclear ability.

There is no way of predicting Hamas' future moves. But if it refrains from joining the Palestinian Authority and its people are convinced that Israel won't lift the siege over Gaza, it is very possible Hamas will inflame the border region again, despite the knowledge that Israel will retaliate with greater firepower. In other words, Israeli deterrence will not work.

As for Syria, it is possible that it will refrain from military moves against Israel in the future as well, but this does not mean it won't continue amassing power to deter Israel and to ensure it is capable of launching an attack, should it so desire. The same can be said of Hezbollah.

As for Iran, even if it attains military nuclear capability, it will probably refrain from using it, in part because of the destructive reaction that would result. Thus, as more and more observers have been saying, Iran does not constitute a threat to Israel's survival. However, if Israel does not make do with deterrence and attacks Iran, the latter is very likely to react in a destructive way.

What are the strategic conclusions of all this? One conclusion is that Israeli leaders must stop spreading the idea that Israel has the ability to take decisive deterrent action and must initiate a military operation every few years to preserve that ability.

Instead of preparing for an attack on Iran, Syria, Hezbollah and Hamas, the government should be investing a lot more in direct attempts to resolve - by negotiations - the conflicts with Syria, Lebanon and the Palestinians. This would also reduce the fear of Iran to a large extent.

The writer is a professor of political science at the Hebrew University of Jerusalem.