David Eshel Tel Aviv

Israel launched Operation Pillar of Defense last November with the killing of Ahmed Jabari in Gaza City by an armed drone. Jabari, commander of Hamas forces in Gaza, was in a car when the missile hit. Israeli officials called it a perfect operation, based on real-time intelligence and precision munitions. Importantly, no civilians were seriously hurt.

Although the strike eliminated an important Hamas leader, its real value was in demonstrating, again, that Israel can act whenever and wherever it wants to protect vital interests. Which in itself leads to a vital question: How much deterrence does Israel need to dissuade enemies from attacking? It is a question that will soon be answered as government and military officials assess the impact that Operation Pillar of Defense had on eliminating threats posed by the rocket arsenals of Hamas and other militants.

The operation lasted from Nov. 14, 2012, until the 21st, when Egypt brokered a ceasefire. Since Operation Cast Lead in 2008, when Israel sought to end rocket attacks on its cities from Gaza, Hamas and other factions had expanded their arsenals to include longer-range rockets. In 2008, Israeli intelligence believed that all factions in Gaza possessed a total of 5,000 rockets; by the outbreak of Pillar of Defense the total was put at 10,000-12,000, including for the first time rockets that could reach Tel Aviv.

Indeed, those rockets were used during the conflict. The deterrence achieved by Operation Cast Lead afforded Israel some breathing space, which was used to develop the Iron Dome counter-rocket, artillery and mortar system that had a remarkable 85% success rate during Pillar of Defense. This provided security to Israelis living within range of the Gaza barrages. With Iron Dome, Israel demonstrated how technology is a game-changer on the modern battlefield. The system gave decision-makers the freedom to act judiciously. In particular, Iron Dome's success made it unnecessary to launch a costly and politically unpopular ground operation into the crowded and dangerous Gaza Strip.

The primary reason behind the government's decision to embark on Pillar of Defense, however, was its assessment that the deterrence it achieved from Operation Cast Lead had eroded, and as a result Hamas, which controls the Gaza Strip, had loosened its reins on other militants, enabling them to fire rockets at Israel.

Not enough time has passed to make a credible assessment of the operation's results and ramifications in rebuilding deterrence. The minimum goal was viable deterrence—that is, convincing Hamas that launching rockets at Israeli towns could endanger its rule in the Gaza Strip.

A second objective was to destroy the rocket-launching capabilities of Hamas and other organizations, or at least reduce their impact through Iron Dome's interception capability. The use of ground forces for an extensive operation remained an option throughout.