The policy of isolating Hamas and applying sanctions to Gaza has been a predictable failure. Violence to both Gazans and Israelis is rising. Economic conditions are ruinous, generating anger and despair. The credibility of Palestinian Authority President Mahmoud Abbas and other pragmatic forces has been grievously damaged.

The peace process is in tatters. Meanwhile, Hamas’s hold on the Gaza Strip, purportedly the principal target of the policy, has been strengthened. Since Hamas assumed full control in June 2007 the already-tight sanctions, imposed following the Islamists’ January 2006 electoral victory, have been tightened further. Israel — upon which Gazans depend almost entirely for relations with the outside world — even curtailed cross-border passenger and goods traffic.

Israel has hardly been alone. The West Bank-based Palestinian Authority, seeking to undermine Hamas’s standing, has done its part to cut off Gaza and prevent the normal functioning of government. Feeble protests aside, the international community has at best been a model of passivity. The logic behind the policy was that by putting pressure on Hamas, they could prevent rocket launches into Israel. This would demonstrate to the Palestinian people that Hamas could not deliver and ought not be trusted.

By boycotting the security, judicial, and other government sectors, the Palestinian Authority turned an intended punitive measure into an unintentional gift, creating a vacuum that Hamas has filled. The absence of any international involvement has meant the absence of leverage. The closure of the crossings has caused the private sector to collapse, eroding ordinary citizens’ traditional coping mechanisms, increasing their dependence on those who govern, and weakening a constituency traditionally loyal to the Palestinian Authority.

Some will argue that the isolation policy is working because Hamas has lost popularity, which even its leaders acknowledge. But intense public frustration in the Gaza Strip cannot be the measure of success. While the continuation of the current policy may be easier to envision, so are its consequences. Hamas will not sit idly by as Gaza is choked.

If current trends continue, we will see increased attacks against Israeli towns and cities as well as the resumption of bombings and attacks inside Israel, like the recent ghastly murder of the eight yeshiva students. Israel will intensify its military incursions, targeted assassinations, and attacks on key installations. And the peace process will vanish entirely, discrediting pragmatic Palestinian leaders. The conflict could then spread to the West Bank or even Lebanon.

Avoiding that worst-case scenario means sharply changing policy course. Engaging Hamas may provide the Islamists with greater international recognition, but acknowledging its role also could mean increasing leverage on it. As it stands, Hamas has nothing to lose. Not surprisingly, it is behaving that way. — The Christian Science Monitor