Israel's military operations harmed the chances of peace in the long term:

The long-term security of Israel rests with a stable peace agreement with the Palestinians, not in attempts to bludgeon Hamas into a truce 'on Israel's terms'. To the extent that Israel's large scale assault on Gaza eliminated the hopes of such an agreement, the attacks worsened Israel's long-term security.(10) Operation Cast Lead ignored history, which teaches that there is no military solution to peace with the Palestinians. As a Daily Star Editorial argued, "For the Israelis, once they have exercised this latest spasm of gratuitous bloodletting, there will be yet another opportunity to accept the oft-proved impossibility of a military solution. The Palestinian people will not be battered into submission, no amount of air strikes will make the core issues in the moribund peace process go away, and all of the same difficult decisions will still be waiting when the dust settles."(18) Thus Operation Cast Lead actually undermined future peace by once more making Israelis believe they can fight their way to a solution, which they cannot. As Nicholas Kristoff argues, "What we’re seeing in the Middle East is the Boomerang Syndrome. Arab terrorism built support for right-wing Israeli politicians, who took harsh actions against Palestinians, who responded with more terrorism, and so on. Extremists on each side sustain the other."(10) Israel cannot stop rocket attacks by military action alone; eventually a political deal will be needed.(19) Operation Cast Lead emboldened the anti-negotiation side of Israeli politics, however, which focus on their claim that Israel should not negotiate with Hamas. However, Hamas was democratically elected, and so Israel must make peace with them. If Hamas was an authoritarian regime, Israel could possible attempt to get rid of it and make peace with the Palestinians in Gaza separately. But, because Hamas was democratically elected, any efforts by Israel to destroy them will be seen in Gaza as an effort to destroy the Palestinians and their democratic will. This would not enable any long-term peace with the Palestinians. Therefore, a long-term peace depends on working with Hamas, rather than attempting to destroy them.(20)  Instead, Israel pursued Operation Cast Lead, which included an Israeli ground assault in Gaza, the excessive force of which is likely to create more terrorists in the long run.(10) The fact that Hamas was always going to survive Israel's assault meant that Operation Cast Lead was always going to help to consolidate the legitimacy of the Hamas movement, and to ensure that all the efforts of Israel to eliminate that fundamental pillar of resistance will produce the reverse result.(22) Israel's offensive gave Iran and its allies a way to pressure Egypt, Jordan and other Arab 'moderates'. Like the Lebanon war of 2006, Israel's battle with Hamas in Gaza produced a schism among Muslim states. Iran and its Lebanon based ally Hezbollah have joined Hamas's Damascus-based leadership in calling for a new intifada, or uprising, against Israel -- and also against the governments of Egypt and Jordan, which are accused of silently supporting Israel's air attacks.(23) Israel’s ruthless attack on Gaza and the massive civilian casualties it has inflicted has severely damaged the nation's moral stature in the world. This moral deficit will cause problems for Israel in its future engagements in the world. Therefore long term peace in the region was harmed by Operation Cast Lead, and so it was not justified.