"What they really need to do is to get Syria to get Hezbollah to stop doing this sh?, and it?s over," said President George W. Bush over an unnoticed open microphone at the St. Petersburg summit last Sunday, but it isn?t really that simple. Hezbollah certainly started the fight (by crossing Israel?s border and taking two soldiers hostage), but it is not clear that either Syria or Iran is the mastermind behind the operation. Sheikh Hassan Nasrallah, the leader of Hezbollah, is perfectly capable of taking this initiative on his own.

Nasrllah knew that the Israeli retaliation for the kidnapping would fall mainly on innocent Lebanese (because they are much easier targets than his elusive guerillas), but he doesn?t care. He had a few surprises up his sleeve, like longer-range rockets that could strike deep into Israel and radar-guided Silk-worm anti-ship missiles to attack the Israeli warships that used to shell the Lebanese coast with impunity. And if he manages to fight Israel to a draw, he will come out of this the most popular Arab leader since Nasser.

General Dan Halutz, the Israeli Chief of Staff, was also spoiling for a fight. His major concern has been that Israel?s "deterrent power" has gone into decline, and he wanted to re-establish it. Some Israeli defence analysts, like Prof. Gerald Steinberg of Bar Ilan University, believe that the plan for the massive strikes against Lebanon has been sitting on the shelf for several years, awaiting a provocation that would justify putting it into effect. But what does "deterrent power" actually mean ?

Understand that, and you understand the remarkable savagery of the Israeli attacks on Lebanon. Of course they are a "disproportionate use of force", as French President Jacques Chirac called them the other day. That is the whole point. Israel?s "deterrent power" lies in its demonstrated will to kill and destroy on a vastly greater scale than anybody attacking it can manage. Its enemies must know that if one Israeli is killed, a dozen or even a hundred Arabs will die.

This has been the dominant concept of Israeli strategy from the very foundation of the state, and the "kill ratio" in all of Israel?s wars down to its invasion of Lebanon in 1982 conformed to that pattern. The first time it didn?t apply was in the struggle between Israeli troops and Hezbollah during Israel?s prolonged occupation of southern Lebanon in 1982-2000, when the Israelis were managing to kill only a few Hezbollah guerillas for each of their own soldiers who died.

Hence the perceived need within the Israeli armed forces to "re-establish deterrence", i.e. to demonstrate that Israel can and may respond with massively disproportionate violence even to minor attacks. The IDF wasn?t actually looking for a fight, but if a fight came along it intended to use the opportunity to make a demonstration of just how big an over-reaction it was capable of.

In the case of the Gaza Strip and the kidnapping of the first Israeli soldier by Hamas militants on 25 June, the operation went more or less according to plan, because the Palestinian militants have little to fight with : the casualty ratio there since the Israelis responded with massive force has been over twenty dead Palestinians for every Israeli killed. But Hezbollah is a much more serious opponent.

After more than a week of mutual bombardment, Hezbollah rockets against Israeli artillery and aircraft, Hezbollah still has at least three-quarters of its rockets left. A large part of northern Israel will remain under attack from the skies -- not very accurate attack, but about one rocket in a hundred kills someone -- unless the Israeli army is willing to occupy all of southern Lebanon again.

Even more worrisome for Israel is the fact that "deterrence" is not really being re-established. A great deal of Lebanon?s civilian infrastructure is being destroyed, but the actual kill ratio is only about six-to-one in Israel?s favour.

This is not just a hiccup ; it is evidence of a slow but inexorable shift in the terms of trade. Israel will remain unbeatable in war for the foreseeable future, but the good old days of cheap and easy victories are not coming back again.