Every day in the Gaza Strip, strategic deterrence - the inhibition of attack by a fear of punishment backed up by superior military power - is being put to the test. The escalating spiral of violence by Israel and Gaza militants indicates not only that deterrence is failing, but also that its effectiveness depends on adherence to fundamental standards of morality.

Some security strategists and just war theorists argue that there may be nothing morally objectionable about deterrence in cases where the lives and welfare of a civilian population are not directly affected. The threat of retaliation that underpins its strategic effectiveness remains implicit and hypothetical. However, when deterrence becomes indistinguishable from collective punishment - barred under international law by Article 33 of the Fourth Geneva Convention - it is far less likely to achieve its intended result.

Israel, which withdrew unilaterally to the periphery of Gaza in September 2005, has been seeking to prevent Palestinian resistance fighters from lobbing rockets into its territory. Shortly after redeploying to the borders of Gaza, Israel severely restricted ties between Gaza and the West Bank, as well as the movement of goods in or out of Gaza. When a pro-Hamas Parliament was elected in a free and fair election in January 2006, the United States and Israel led a campaign to prevent all banks, including Arab and Islamic banks, from dealing with the new government.

Israel has consistently rejected Hamas' repeated offers of a cease-fire agreement in exchange for the lifting of the siege on Gaza. Public opinion polls carried out by the Dialog company and published in the Israeli daily Haaretz have shown that 64 percent of Israelis support an official dialogue with Hamas. But the Israeli government and army refuse, calling Hamas "terrorists" in order to deny the movement legitimacy, despite previously reaching understandings in southern Lebanon with Hizbullah, which they also consider a "terrorist organization."

The Israelis seem to believe that their only option is to tighten the screws on Gaza. In the name of deterrence, movement of people and goods has been almost entirely restricted. Yet the Palestinian resistance has responded with more rocket attacks. Israeli assassination campaigns against militants have merely led to further escalation on the Palestinian side. Indeed, every time Israel's deterrence efforts fail to produce the desired result, it ratchets up the siege in the hope that this will deliver some kind of knockout punch.

The result has been a clear case of collective punishment in one of the most densely populated places on earth, with 3,823 persons per square kilometer. Upon visiting Gaza, John Dugard, the United Nations' Special Rapporteur on Human Rights, said that "Gaza is a prison and Israel seems to have thrown away the key."

In January, for example, Israel began using its monopoly on fuel supplies to punish Palestinians, a decision condemned the following month by Human Rights Watch. Joe Stork, Human Rights Watch's Middle East director, rejected Israel's justification of the fuel cuts as a way to force Palestinian armed groups to stop their rocket and suicide attacks. According to Stork, "the cuts are seriously affecting civilians who have nothing to do with these armed groups, and that violates a fundamental principle of the laws of war."

Likewise, following the Israeli air strikes on Gaza in early March that killed more than 100 Palestinians, UN Secretary General Ban Ki-moon was moved to "condemn the disproportionate and excessive use of force that has killed and injured so many civilians, including children."

Notwithstanding the UN secretary general's statement, Israel claimed self-defense, as the air strikes followed a rocket attack from Gaza that killed an Israeli civilian in the border town of Sderot. However, in his book "Crimes of War," Michael Byers, a Duke University law professor, argues that the use of force in self-defense "must not be unreasonable or excessive," and with regard to anticipatory action, the necessity must be "instant, overwhelming, leaving no choice of means, and no moment of deliberation."

In fact, Israel persistently conflates self-defense and deterrence, while employing collective punishment to advance its strategic aims. This conception of deterrence failed in Lebanon in 2006, with Israel forced to accept a UN-sponsored cease-fire agreement, and it is no more likely to succeed in Gaza. Indeed, opinion polls conducted in Gaza show a spike in support for Hamas after every Israeli escalation.

The international community must act quickly to force the Israelis to abandon its deterrence strategy and instead work on reaching an understanding that can result in a cessation of attacks by both sides. Only such an understanding can permit a start to the groundwork needed for a political resolution that can permanently end both the siege of Gaza and the occupation of Palestinian lands.