Nearly four years after Operation Cast Lead, a new battle to restore security for the South has begun. The deterrence levels gained by Israel in the 2009 operation have run out, in great part due to the rise of the Muslim Brotherhood in Egypt.With Hamas feeling confident over the ascendancy of its fellow Islamists in the region, and the emergence of a new patron in Cairo, it and Islamic Jihad chipped away at Israeli deterrence, attempting to set new rules by preventing the IDF from carrying out vital security missions on the Gaza border.The current operation underway in Gaza is based on a flexible approach. It began by sending a strong message to Hamas: that it must choose between the survival of its members and the continued firing of rockets at southern cities, towns and villages. At the same time, Israel has left Hamas with an exit. Should it decrease the rocket attacks, the IDF will scale back its operation.The aim is not to topple the Hamas regime – at least not at this stage.Israel once again has proved that its intelligence capabilities in Gaza are superb not only by targeting the head of the rocket- launching machine, Ahmed Jabari, but also by removing most of Hamas’s long-range underground rocket launchers in the first wave of air strikes.The ball is now in Hamas’s court. If it chooses to continue to lash out at Israel’s civilians, it could find itself face to face with a ground offensive, a development that would take the current operation to a new level.Operation Pillar of Defense is also a message to the wider region, now filling up with Islamist forces: Israel will not be deterred from taking basic steps to defend its civilians.As it built up its rocket arsenals, Hamas and the other factions responded to Israel’s measures to secure the border with more and more indiscriminate rocket barrages on the long-suffering South, filling the lives of hundreds of thousands of civilians with dread, trauma and disruption.Hamas has overplayed its hand. It mistook Israeli restraint for weakness.