The terror bombing in Jerusalem was another malicious product, another massacre of civilians on the endless production line created by the Hamas decision to conduct a war to end all wars against Israel. It was not the attempted assassination of Hamas leader Abdel Aziz Rantisi that spawned yesterday's attack, just as the attack on the bus did not spawn the planned assassination of Tito Massoud shortly afterward.

Both sides exchange blows when they can, and the road map of the politicians has become the map of the road on which were moving the bombed Egged bus in Jerusalem and the rocketed cars in Gaza. It's a parallel reality, not mutual nor equal.

The basic responsibility, the direct cause of the escalation that now threatens the political process and which sent the number of Israeli casualties in the three-year war over the 900 mark, sits on the shoulders of the Palestinians who reject any peace deal - particularly Hamas, which is growing in strength and has produced about half the planned and executed operations.

But the crimes of the Hamas, Islamic Jihad, Tanzim and the Popular and Democratic Fronts are not the only elements in the imbroglio created in the last few weeks. Less than their contribution, but nonetheless serious, were the sins of Ariel Sharon and the mistakes of George Bush.

By deciding to strike at Abdel Aziz Rantisi, before the attack on the bus, instead of waiting for it, as common sense would dictate, the prime minister acted as the Likud leader, the head of the right, who needed to cover his flank when he went to dismantle the illegal outposts.

Rantisi was incriminated in the attack on the Erez Junction army base, and would direct future attacks. But killing him would not have obstructed a single terrorist action, only punish him and send a signal to his colleagues.

Punishments and signals can be reasonable goals under certain circumstances, but they should not be confused with foiling an attack. The appropriate time for an all-out offensive or assassination of the entire Hamas leadership is after a major terrorist outrage, one of the dozens that are being planned - not before one.

Any military operation needs to have a political context. Sharon's first sin was the political context of the assassination attempt on Rantisi on Tuesday, before any major attack inside Israel. The second sin was that the assassination attempt gave the Hamas a context for their strike in Jerusalem, even though, as far as is known, it was planned without any connection to what happened in Gaza on Tuesday.

Sharon's partners in the failure, Defense Minister Shaul Mofaz and Chief of Staff Moshe Ya'alon, have lost important points in the last two days toward their separate striving for images of seriousness and professionalism. The general staff is supposed to think ahead to the next battle in the long campaign; the officers should have known that even if they could barely excuse the attack on Rantisi, the need to excuse it would have meant it was a loss.

Ya'alon will have to explain what's gone wrong in the army - its judgment or the loss of courage on the part of the officers to tell Sharon and Mofaz what their decision could mean.

Mofaz meanwhile still hasn't learned how to think as a national policy maker, in which complexity and nuance instead of force is the main instrument. Yesterday at the budget meeting in the cabinet, he threatened he could not be responsible for security if another cut is imposed on the defense budget.

That's a frightening threat, one more nightmare of the many that already keep Israelis awake. He did not threaten to resign if Rantisi was targeted after the Aqaba summit, or if there was a delay in building the main part of the separation fence, the Jerusalem envelope, or in the south.

One of Bush's mistakes is connected to the fence. Instead of supporting it in principle as a temporary shock absorber that would not affect the final arrangements reached through negotiations, and instead of insisting the fence not be too far east of the Green line, the administration opposed it in its entirety.

Without a fence, there won't be defense, and without defense, there will be operations to foil terror both small and medium sized - and if they don't work, major operations, as well. Bush's second mistake was giving into the Palestinian demand, supported by the three partners to the Quartet, to include the outpost evacuations as part of the first phase of the road map, instead of making do with security and relieving the suffocating pressures on the Palestinian population.

The linkage between the outposts and the Palestinian fight against terror contributed to the escalation. The Israeli government must evacuate the outposts for its own reasons - law and order, and helping the Abu Mazen government, irrespective of Abu Mazen's actions. Since he has not done anything to foil the attacks, but Sharon has started to evacuate Israelis from outposts, Sharon was forced to balance his actions with a demonstration of force against the Palestinians.

Bush does not claim to be knowledgeable about the details. From his public statements after Aqaba one could learn he thought Knesset is synonymous with the Israeli government and that the assistant secretary of state for Near East affairs, William Burns, holds a deputy secretary rank.

Last night, in an emotional condemnation of the massacre in Jerusalem, Bush signaled he would back off from the details to an overall policy - fight terror, in the Hamas and the rest of the organizations, and not relate to every specific move by Israel.

Bush's approach, since 9/11 and apparently again after yesterday, will slightly increase Israel's maneuverability against the terrorists but unlike the past it will have to consider the negative impact of its moves on Abu Mazen and his colleagues. That does not necessarily guarantee balanced decision making.

Yitzhak Rabin, in similar circumstances of Hamas rampages while conducting delicate contacts with the PLO, was swept into over-reaction after the murder of a policeman. He failed, sending 415 Hamas leaders into exile in Lebanon - including Rantisi.