There has been a single assumption that has shaped Arab-Israeli relations since 1948: that Israel could decide, if it wished, to resort to war and impose its will on Arab armies. That assumption shaped all political considerations in the region. If Israel is no longer capable of doing that, it follows that a range of political assumptions also are untrue. Consider Jordan: Since 1970, Israel has been the guarantor of Jordanian national security. Consider Egypt: Since Camp David, Egypt has refused to engage Israel militarily. Both of these political certainties have been based on a military certainty — and if that dissolves, so does everything else.

Hezbollah has been fighting a simple, conventional war. It has relied on fortifications, pre-positioned supplies and motivated troops. Israel has sought to defeat Hezbollah without incurring extensive casualties. The first strategy was the air campaign. The second strategy was a complex warfighting-diplomacy strategy designed to achieve Israel’s ends without having to systematically destroy Hezbollah. The end result of this strategy — if it is carried out to its logical conclusion — is that Hezbollah will have fought and survived, and that in fighting, it will have shaped Israeli political decisions. In other words, we will have moved from a world in which Israel’s military force trumps all other considerations to a world in which Israeli military power is circumscribed by Arab power.

It seems clear that Israel could have crushed Hezbollah if it was willing to spend the lives. Prime Minister Ehud Olmert’s view seems to have been the rational one — that the rockets Hezbollah has been firing at Israel were creating fewer casualties by far than a war would. On that cost-benefit analysis, Olmert not only was correct, but followed the reasoning of Ariel Sharon. Sharon’s strategy focused on building barriers between Israel and Arabs in order to avoid the costs and casualties involved in counter-insurgency operations. Olmert has extended that logic to southern Lebanon, seeking a low-cost solution to the Hezbollah threat.

In so doing, Olmert, intentionally or not, has shifted the basic architecture of Israel’s strategic policy. He has avoided an extravagant cost in lives, but in so doing, has undermined the military certainty that was the foundation of Israeli national security. Hezbollah was able to start a war and has survived it defensively. In due course, an Arab force will be able to start an offensive war and win it. There is no inherent reason that an Arab army cannot defeat an Israeli army. Whether there is a cease-fire or not, the psychological foundation of Israeli power has been breached.

Meanwhile, a furious battle continues within Israel. On one side, Olmert is arguing that a diplomatic solution achieves Israel’s ends without costing Israeli lives. On the other side, the military and the Likud Party are arguing that Olmert has defined the end too narrowly. If a low-cost solution to the current crisis means a newly self-confident Hezbollah swelling with fresh recruits, then the price will merely have been put off to another day.

At this point, the battle shifts from Lebanon to the corridors of power in Israel. The test is whether Olmert has the political power in the country to let the war end here. Part of the question is what the military will do on the ground in Lebanon. There is the example of Ariel Sharon fighting after a cease-fire regarding forces in Lebanon was announced. The IDF is upset enough to do that here, and the terms of the cease-fire deal leave enough room to drive a tank through. But there is also going to be an attack on Olmert’s government if there is a cease-fire. It isn’t clear that he can survive with this outcome on the ground.