In March 2004, an IAF-fired missile hit the wheelchair Hamas spiritual leader Sheikh Ahmed Yassin was sitting on as he left a mosque in Gaza City following early morning prayers. Three weeks later, his successor, Abdel Aziz Rantisi, was killed in similar fashion. Israel went into a defensive mode, preparing for a Kassam rocket and suicide-bomb onslaught, which never came. Instead, Hamas asked for a cease-fire. The sharp escalation in targeted killings and Gaza air strikes since Monday night is an attempt by the defense establishment to try and copy the success from 2004. While the hudna (cease-fire) then did not last for long, it did create a lull in attempts by Hamas to infiltrate suicide bombers into Israeli cities. The assassination of Gaza's Islamic Jihad chief, Majed Harazin, and the group's head of rocket production, Karim al-Dahdouh, together with another eight operatives is a huge loss for the terrorist group, but also a loud and clear message to Hamas. While Hamas is behind the mortar fire into Israel, according to the IDF, it rarely has is own operatives launch Kassams. Instead of getting its hands dirty, it passes on the rockets to Islamic Jihad or the Popular Resistance Committees. For Israel, this does not make much of a difference; Hamas leaders are already targets due to their involvement in mortar and other terrorist attacks. But the difference is that if Israel begins knocking off Hamas leaders, the potential for a repeat of the 2004 hudna would turn instead into a dramatic escalation in Gaza, which could lead to direct Hamas involvement in Kassam attacks and an unprecedented increase in rocket fire. According to official estimates, Hamas is capable of firing dozens of rockets a day into Israel. These estimates were behind evacuation plans that were drawn up last summer for Gaza Strip periphery communities in the event of a large-scale ground invasion into Gaza. Transportation Minister Shaul Mofaz is a proponent of increasing the targeted killings as an effective way to stop the rocket attacks. "We need to work in a way that is clear that they will pay a price for all Kassam attacks," he recently told The Jerusalem Post. "The leadership needs to feel hunted and persecuted." While this option has the potential to minimize the rocket fire, it is extremely difficult to obtain the needed intelligence to carry out the strikes. There is also great risk involved. When putting all of its emphasis on targeted strikes, the IDF risks botching a mission and repeating the events of the summer of 2006, when within eight days three air strikes killed 13 Palestinian civilians. This week's events stem from a number of elements. Firstly, the political establishment is under pressure to do something in face of the increasing bombardment of Sderot. Secondly, obtaining of quality intelligence is not so easy to come by, and once you have, it you might as well use it. IDF officers, who are usually quick to take credit for such operations, sang a different tune on Tuesday and gave praise to the Shin Bet (Israel Security Agency), which provided the intelligence that led to the targeted killings of the Islamic Jihad chiefs. But what is really behind the increase in targeted killings is Prime Minister Ehud Olmert's desire to stave off a large-scale operation into Gaza that only a few weeks ago Defense Minister Ehud Barak was saying was inevitable. There are a number of factors behind this. Firstly the timing: Israel is less than a month after the Annapolis peace summit, a week after starting full-fledged negotiations with the Palestinians and only weeks away from US President George W. Bush's historic visit to Jerusalem. A large-scale operation in Gaza, officials said, would without a doubt prevent all of this from happening. The second and more fundamental factor has to do with the risks involved in a large-scale operation. Contrary to public thinking and to remarks he made last week, IDF Chief of General Staff Lt.-Gen. Gabi Ashkenazi is not today in favor of a massive invasion into Gaza. Firstly, there is the question of the "day after." If Israel invades Gaza, cleanses it of Hamas, Palestinian Authority President Mahmoud Abbas is still not capable of grabbing the reins and taking control, and the last thing Israel wants is to stay there and occupy Gaza. An operation in Gaza would be limited by time, but it would also not be in-and-out. To really hurt Hamas and Islamic Jihad and impair their ability to fire rockets, IDF troops would need to enter deep into the densely populated and heavily built-up Palestinian territory to hunt down terrorist suspects, Kassam manufacturing plants and weapons caches. Troops would also most likely take up positions along the Philadelphi Corridor in southern Gaza where dozens of tunnels are used to smuggle weapons and explosives into Gaza. All of this means heavy casualties on the Israeli side, with some defense officials predicting that the final number could surpass the 119 soldiers killed in the Second Lebanon War. As a result, Ashkenazi today prefers a different approach to Gaza - a complete disengagement from the territory, including the closure of all the crossings as well as a complete stop to the delivery of fuel and electricity. Under this scenario, Israel would only work to ensure that a humanitarian crisis does not develop there, but no more. This is an extreme scenario, one that the government would have difficulty approving, particularly in light of the difficulty it has faced in cutting a minor amount of the electricity it currently supplies to Gaza. Defense officials said Tuesday that the targeted killings would continue. Will they replace the ground invasion? Only time will tell.