For 45 days, Israel has been searching for the tiebreaker in its confrontation with Hamas in the Gaza Strip. The successful interceptions by the Iron Dome system, the destruction of 32 Hamas attack tunnels, the enormous destruction wrought in towns and neighborhoods close to the border — these were not enough to convince the Israeli public of a tangible victory.

The relatively high number of casualties sustained while searching for tunnels, the ongoing rocket fire (especially in the south) and Hamas’ repeated violation of cease-fires have given rise to a sense of confusion, and even impotence, in Israel. When residents of kibbutzim are afraid to return home and cabinet ministers publicly attack the prime minister for his weakness vis-à-vis Hamas, it’s difficult to speak of a decisive victory.

The assassination campaign launched by Israel this week reflects an attempt to break out of a military standstill and compel Hamas to accept a cease-fire. If the campaign ends successfully — assuming Hamas doesn’t exact a heavy price in countermeasures — the assassinations will help Netanyahu get rid of two burdens: the external pestering by Hamas and the internal political backbiting by cabinet members Avigdor Lieberman and Naftali Bennett.

The fate of Mohammed Deif, the commander of Hamas’ military wing, is still unknown. However, Hamas admitted on Thursday that two of its senior commanders, Mohammed Abu Shamaleh and Raed Attar, considered numbers 3 and 4 in its military wing, were killed in an air force strike in the Rafah area. Other senior officials are also in Israel’s sights. These are the hardest days yet for Hamas since the war started.

The arguments regarding the effectiveness of targeted assassinations have been going on for two decades. As opposed to instances in which serious and proven operational damage was caused, such as the killing of Hezbollah’s Imad Mughniyeh in 2008 and of the Islamic Jihad’s Fathi Shikakai in 1995, opponents of targeted assassinations will point out cases in which removal of a bitter enemy led to the appearance of a worse one (Hassan Nasrallah replaced Abbas Musawi as secretary general of Hezbollah in 1992; Deif replaced Ahmed Jabari as the head of the military wing of Hamas in 2012). At this point there is a consensus in Israel’s political leadership that assassinations are useful. This may stem from the lack of other alternatives.

Israel tried to hit senior Hamas figures from the outset of the war. Intelligence gaps as well as concerns over causing massive civilian casualties around their hiding places made this difficult. It seems as though these figures devised a formula for survival. Their maintaining of strict security measures made their exposure difficult. The network of tunnels and underground bunkers protected them, and the presence of civilians in adjacent buildings extended their protective umbrella. This envelope was breached in the attempt on Deif’s life, continuing with the assassinations of Attar and Abu Shamaleh.

These targeted assassinations followed the fruition of several processes. Military Intelligence and mainly the Shin Bet security services delivered information on their exact whereabouts in real time. In addition there was an apparent technological-operational factor which enabled the breakthrough. Apparently the air force used four one-ton bombs as well as four other smaller penetrating bombs in order to destroy the house Deif was suspected of being in. Aerial photos show that the house was completely demolished. More significantly, the penetrating bombs erode the secure space that senior Hamas officials created for themselves underground.

A third factor is the amount of civilian lives that Israel is willing to risk in order to target these senior figures. Before the attack on Deif it was estimated that up to 15 people may be in the building, mainly civilians. Until last night seven bodies were removed from the rubble, including Deif’s wife and two children. More bodies may still be buried there. Although Israel is not officially commenting, the leadership (with Netanyahu personally approving such strikes) made a cold calculation. The assassinations are needed to urge Hamas to cease firing. Civilians are killed in these operations, but many more will die if the IDF returns in a massive ground operation in the event that Hamas continues firing rockets. This consideration bends the rules regarding innocent civilian casualties.

Remaining Hamas leaders understand very well the message embedded in Israel’s moves: Your network has been penetrated (on the intelligence front) and pierced (as relates to underground shelter). If you don’t stop now this will continue and your families may be hurt as well. For the first time it appeared that Hamas was caught off balance on Thursday. The killing of Attar and Abu Shamaleh even disrupted intentions to target Ben Gurion Airport. Up to now Hamas has shown total control of its firing, which unfolded along a well-laid plan. On Thursday morning they seemed to be more preoccupied with personal survival than with fulfilling publicized promises.

Abu Shimaleh and Attar were veterans of the senior leadership of the military wing, people whom Deif gathered around himself in the 1990s. Recently they were known to have shared a safe house in Rafah. Presumably they were afraid to leave it after the IDF targeted many other hiding places in the area. It is possible that the shock caused by the attempt on Deif’s life impacted their behavior and enabled their assassination during consultations with other senior officials. No one will shed a tear for Raed Attar in Cairo – they had a long account to settle with him, following his aid to global Jihadist groups operating in Sinai.

On Wednesday morning there was concern in Israel that Deif had yet again survived a fifth (at least) attempt to assassinate him. Then there was a weak denial of his death by the military wing. Yesterday there was some optimism in Israel. It’s now not clear if even Hamas knows what happened to Deif. In any case, if he was killed or injured it will take time before a replacement with a similar murderous bent can be found. Deif was behind the murderous attack tunnels and shaped Hamas’ operational strategy. Will the string of assassinations force Hamas back to negotiations in Cairo, showing more flexibility? Despite the blows it suffered, it’s difficult to predict with any certainty. It will probably try to carry out a quick reprisal such as using an attack tunnel, if one remains, firing anti-tank missiles on the border and the usual attempt to abduct a soldier.