Operation Defensive Shield began on March 29 and ended on April 10, 2002. It was the first large-scale operation initiated by Israel since the beginning of the second intifada in September 2000 that engaged a large part of the West Bank controlled by the Palestinian Authority. It was a turning point in Israel's struggle to stop the bloodshed caused by this intifada. The reason for the decision to launch the operation was an increase in Palestinian suicide bombings in Israeli cities that reached its peak on March 27 when 30 civilians were murdered during a Passover holiday dinner at Park hotel in Netanya.

A large Israel Defense Forces contingent numbering more than 20,000 soldiers participated in the operation. Their declared purpose was to destroy the terrorist infrastructure in the West Bank, but the operation targeted not only armed groups that participated in the terrorist operations.

The perception in Israel was that this armed intifada was planned, initiated, organized and supported by PA President Yasser Arafat.

Therefore all PA infrastructure and institutes were targeted, with special emphasis on security organs, which were attacked and disarmed. The muqataa, the campus of PA government buildings, was placed under a siege that was effectively lifted only after the death of Arafat. One particularly striking case was the destruction of the headquarters of West Bank Preventive Security headed by Jibril Rajoub. It was attacked even though Rajoub had not allowed the organization under his command to take part or assist in any terrorist operation.

The perception in Israel that the operation brought about an immediate and dramatic decrease in the level of Palestinian terrorist operations was in fact not validated by statistics for the months that followed this operation. It seems that the direct damage caused to the armed groups involved in these terrorist actions was balanced by an increase in motivation to take revenge and fight Israel. The real decrease began only in the next year, 2003.

Nevertheless, the operation made a great contribution to Israel's success in eventually suppressing terrorist activities because through this operation the IDF and Israel's other security organs regained their freedom of action in the West Bank. Before the operation, there was much concern in Israel that the PA's security organs would prevent independent Israeli security activities in the areas under their control. After the disarming of these organs, complete Israeli control and full freedom of action were achieved. This facilitated more effective intelligence collection and the dismantling of terrorist cells and interception of terrorists before they could reach their targets.

This approach also reflected a clear shift in Israeli counter-terrorism strategy. Before the operation it was based on defensive measures, punitive operations against perpetrators of terrorist operations and pressure on the PA government to comply with its commitments to fight terrorism. After the operation, the strategy was based on full neutralization of the PA and independent preventive operations by Israeli security forces.

However, a lot of collateral damage was also caused by the operation: the PA capacity to rule and deliver on law and order was completely destroyed. This had several primary ramifications.

On the political level, the operation destroyed the Palestinian partner for potential agreements and contributed to a deeply-rooted mistrust among the Israeli public regarding the feasibility of having such a partner. When Arafat was alive, the argument was that he was not a partner because of his bad intentions; he did not want peace with Israel. After his death there was no doubt concerning the peaceful intentions of his successor, but then the argument was that the PA had no security capabilities and only Israeli forces could take care of security in the West Bank.

At the same time, in areas under theoretical Palestinian control there emerged a chaotic situation of lawlessness in which armed gangs, private militias and criminals roamed and operated freely. They were tolerated by Israel as long as they did not target it. Palestinian citizens completely lost trust in the PA's leadership and political infrastructure. This was one of the main causes of the Hamas victory in the January 2006 elections.

It took many years and much assistance from the United States and European Union until the PA's security capabilities were rebuilt--and still Israelis do not trust their Palestinian partner.

More careful planning and execution of Operation Defensive Shield and its follow- ups, taking into account future political consequences, would apparently have led to better results. These would have comprised a better distinction between "friend and foe" and possibly more emphasis on devising ways to maintain a credible Palestinian partner for future political agreements.