The biggest problem for the Shin Bet security service is the wide gap between its successes and failures. The Shin Bet's operational successes, with the assistance of the IDF and the police, in assassinating Palestinians involved in planning terror attacks, has increased the determination of the comrades of those who have been assassinated, and the organizations to which they belong, to retaliate in a similar fashion.

Nevertheless, the failures in foiling counter-assassinations will encourage more Palestinians, and maybe others who work independently or are sent by Iran, to try and take advantage of the Shin Bet security breach.

The Shin Bet has been highly successful when it comes to the intelligence dimension in thwarting attacks, as well as in intercepting a lot of information regarding the preparation of attacks. Often, as a result, in six out of seven events the information flows so swiftly that terrorist cells are stopped before they reach their target. The seventh cell, however, which slips through the net is enough for many to be killed in shooting or bomb attacks. Without these successes, however, the number of casualties would be far greater.

The key is intelligence, and it is excellent. But without specific intelligence on an assassination plot, protection breaks down. Rehavam Ze'evi, who served as the advisor on terror to prime minister Yitzhak Rabin in the mid 1970s, conducted security inspections abroad, and should have understood that what happened would be one of the results of neglecting his personal security.

The assumption that assassinations of senior Palestinian officials would also expose their Israeli counterparts to assassination attempts was one of the reasons – not the only reason, and not even the most important one – why the political leadership stopped short of ordering hits on the top Palestinian political echelon. Tanzim heads or leaders who wear two hats - as Tanzim commanders as well as commanders of the PA security apparatuses – benefited from this ambiguity. Israeli cabinet ministers, advised by legal and security officials, were deterred by both the political and personal price of killing their counterparts in the Palestinian Authority.

There is no realistic or imaginary way to surround every VIP with a hermetic ring of guards, because the convoluted unity government has 40 ministers and deputy ministers, will impose an unbearable economic burden on the Treasury. It will also be a personally invasive arrangement for the ministers.

The assailant always has the advantage: he can choose the time, the place and the method by which to strike; he can plan the attack; and even retreat and wait for another opportunity if he fears exposure or failure (even if he plans to commit suicide in the attack.)

Had the Palestinian organizations looked to target any senior personality, from among the ministers or senior IDF officers, for example, who are recognizable – by their appearance or the cars they drive – they could have positioned assassins near their work places in Jerusalem or Tel Aviv, details of which frequently appear in the media. These assassins could have been equipped with lenses, for cameras or a sniper's rifle, or with even heavier weapons.

They have not done so until now, and it is possible – the investigation will determine this quickly – that they had reason to focus on certain personalities, among them Ze'evi. His daily routine and movements made it easier for the assassins to operate. If there was another assassin near the door of his hotel room (the other cell member – perhaps a third man – followed Ze'evi into the dining room and notified the others of his arrival), it is possible that the second assassin was meant to target the bodyguard, had Ze'evi been escorted by one.

VIPs who are under guard – or those without – can make life harder for assassins by changing their daily routines. They could do this by not staying in the same hotel and the same room, and can be more flexible regarding the time they open the door every morning to pick up their newspaper, or when they go out for a jog.

After the assassination of Hezbollah secretary general Abbas Mussawi, Air Force officers who were in the chain of command of the combat helicopters that killed Musawi, were warned they might be targets for assassination. They were asked to drive change the roads they regularly drove on, from time to time. One of them, who had only one access road to his moshav where he lived, obeyed the warnings by building another road to his home using a bulldozer taken from a nearby military base.