Rabin's cool use of ruthless force: Israel is taking a calculated gamble, writes Sarah Helm in Jerusalem

NOT for the first time Yitzhak Rabin, the Israeli Prime Minister, is justifying his use of brute force on grounds that it is the only way to achieve peace. This time he is bombarding Lebanese towns and villages, forcing a mass flight of civilians, claiming this will isolate the Islamic militants of Hizbollah, and force Lebanon on to the peace process agenda.

When Israel's action in Lebanon began on Sunday there was a case for saying Israel had been pushed into limited retaliation against Hizbollah. The Lebanese Shia militia, armed by Iran and supported by Syria, had increased attacks on Israeli targets recently. Hizbollah opposes the occupation by Israeli forces of a strip of land in south Lebanon which Israel guards for its security. In recent weeks the gunmen have been successfully attacking Israeli targets in the strip. Unless Hizbollah were restrained, Israel argued, its attacks would escalate.

After four days of bombardment, however, it is now clear that Mr Rabin never really expected just to 'restrain' Hizbollah. This week's action is part of a broad, radical strategy to achieve, by increasingly ruthless means, far-reaching military and diplomatic ends. The Israeli assessment, put with ever-greater confidence by government officials, is this. Massive use of force to smoke out Hizbollah in Lebanon is unlikely to excite major international revulsion, even if civilians are targeted. The world has changed since Israel's previous ill-fated Lebanon excursions and is nowadays 'understanding', say officials.

Hizbollah is supported by Syria and therefore tolerated by Lebanon, which moves to Syria's tune. But Syria is nowadays committed to the peace process and unlikely to retaliate too precipitously, therefore, to Israel's offensive. And Lebanon, recovering from its civil war, would like to be rid of Hizbollah anyway. All the two governments need to nudge them into taking their own measures against Hizbollah is public pressure from inside Lebanon. The bombardment brings that pressure to bear, creating refugees who, because of their plight, abandon all support for the militants in their midst and call for their government to intervene.

Such a process will take time, Israeli officials admit, but they are prepared to wait. Enter, Warren Christopher, US Secretary of State, who arrives in Israel on Saturday, when the Israeli action is expected to halt, at least temporarily. Israel will use Mr Christopher's presence to switch from its military to a diplomatic offensive.

Israeli officials say that, using US channels, Israel will show readiness to make new compromises over its presence in Lebanon, in the context of the current round of peace talks. Mr Rabin is reported to be prepared to make a clear commitment to withdraw all Israeli forces from the south, in return for cast-iron guarantees from Lebanon that the Lebanese army will move into the area and disarm Hizbollah, and from Syria that it withdraws all support from the militia.

That is a summary of Israeli theory. But it takes little or no account of evidence on the ground: that the violence is achieving a momentum of its own.

Israel has as yet been given no signals that Syria is ready to curb Hizbollah. Rather, Syria is muttering about war. Hizbollah, meanwhile, has refused to be cowed, forcing the Israeli army further to intensify its raids. Mr Rabin is now set on a course which demands he find means to flatten Hizbollah or lose face at home. In the absence of international condemnation, he is in a determined buoyant mood, and a further and more dramatic escalation including a ground offensive cannot now be ruled out.

Whatever Mr Rabin's ends in this conflict, there was increasing doubt last night that they could be achieved. There was no doubt that the means being used to achieve them are unjustified.