Hamas’s political bureau chief, Khaled Mashaal, has ordered his organization in Gaza to reject Israel’s truce offer, according to the latest evaluations in the Israeli defense establishment.Mashaal, who is comfortably based in Qatar, far from the fighting, as well as two Hamas leaders in Gaza – Muhammad Deif, head of Izzadin Kassam, Hamas’s military wing, and Ismail Haniyeh, who heads Hamas’s political wing – are the triangle of decision-makers who plot the organization’s next moves.According to assessments in Israel, Mashaal was the voice that ensured that Hamas continues to fire rockets at Israeli cities.This despite the fact that Hamas has lost some 100 members, including senior field commanders, and that its rocket- firing capabilities have sustained a serious blow in nine days of Israel Air Force strikes, each based on quality intelligence data.Hamas lost many of its rocket-production facilities, more than a third of its rocket arsenal, and a series of command and control bases hidden in the homes of its battalion and brigade commanders.Yet the organization is keen on proving to Israel that it has retained its offensive capabilities and has not lost its will to use them to terrorize Israeli civilians. It has rejected the terms offered to it by Egypt, which, in Hamas’s view, failed to address its financial concerns (which go to the heart of Hamas’s ability to maintain power) and its need to pay its members in Gaza $20 million a month.Hamas’s firepower has been rendered highly ineffective thanks to the advanced Iron Dome air-defense system. The terrorist organization’s carefully planned tunnel attacks, and naval raids, all ended in failure.As a result, its ability to send millions of Israelis fleeing for cover and disrupt daily life here is the only semblance of a “victory” picture it has been able to achieve.Now, it seems, Hamas wishes to drive home the point that it can continue doing this despite Israel’s devastating firepower. That creates considerable difficulties for Israel’s doctrine of deterrence.Hamas’s own doctrine, designed for guerrilla-terrorist warfare, holds that the organization must be able to maintain rocket fire on Israel for at least two weeks, and it is five days short of achieving that goal, despite the misery it has brought to the civilian population of Gaza, which it uses mercilessly as a human shield.Thus far, the IDF’s goal in this operation has not been to destroy all of Hamas’s rocket-firing capabilities but, rather, to inflict sufficient damage so that Hamas loses the incentive to stay in the ring or to return to it for years to come.That Hamas has chosen to keep going, despite bleeding profusely, is a challenge to the deterrence doctrine – a challenge that is being carefully watched by Hezbollah in Lebanon, whose rocket arsenal dwarfs that of Hamas.This appears to leave little option for Israel but to proceed to stage two of its operation. Stage two is not limited to the goal of reinstating Israeli deterrence. Rather, it is aimed at systematically destroying Hamas’s assets and ability to attack Israel. The use of ground forces is an intrinsic component in realizing this goal.While guided air force missiles can do much, Israel will not fire them if dozens of civilians in an apartment building are being used by Hamas to protect rocket launchers and senior Hamas leaders.Additionally, air power has its limitations against the growing threat of tunnels. Hamas has dug a network of bomb-filled tunnels around the border area with Israel, and plans to use them to infiltrate the South, massacre civilians, and attack military positions.The deployment of ground forces is itself a phased process. The broader the military operation against Hamas becomes, the more Israel’s goal shifts from deterrence to outright military victory.The experience of Israel’s military planners tells them that toppling the Hamas regime, while emotionally satisfying to many Israelis fed up with being terrorized, is not necessarily in Israel’s long-term strategic interests. It remains far from clear who might replace Hamas, and Gaza could turn into a Somalia- like strip of land filled with Islamic State militias that cannot be deterred at all.Nevertheless, if Hamas continues to push the envelope, it may force Israel to not only launch a limited ground operation but, eventually, to expand it and go all the way, uprooting the whole of Izzadin Kassam from Gaza. This process could take up to two years.Once the government orders the IDF to initiate the second stage of the operation, Hamas will lose the ability to seek an end to the conflict.If it continues to rain down rockets on Israel, it might end up losing its military wing altogether, and whatever concerns over who might replace it would become secondary to the IDF’s obligation to silence the rockets.