Ten years after Israel evacuated the Jewish communities in the Gaza Strip and parts of northern Samaria, very few – whether on the Right or on the Left or in the Center – are willing to stand wholeheartedly behind what is referred to as “the disengagement.”Opposition leader Isaac Herzog recently referred to the pullout as a “mistake,” as did Shimon Peres some time ago.And although Benjamin Netanyahu voted in favor of the disengagement plan on October 26, 2004, he resigned in protest on August 8, 2005, shortly before it was implemented, and has been a leading critic ever since.Public opinion has shifted significantly over the past decade. If in the months leading up to the pullout polls consistently showed a strong majority in favor, at least one recent survey shows that the situation has changed.According to a poll conducted in July for the Begin-Sadat Center of Strategic Studies, 63 percent of respondents claimed they were against the evacuation at the time, while 51% said Israelis should move back to Gaza Strip. Clearly, some respondents lied about their past support for the pullout out of a feeling of regret.It would be unfair, however, to claim that the disengagement brought only damage upon Israel.From a demographic perspective, Israel ceased to be responsible for more than a million Palestinians in Gaza.Any discussion today of the “demographic time bomb” – the strongest argument against annexation or a one-state solution – leaves out of the equation Gaza’s Palestinians.And though critics claim the pullout unleashed rocket and mortar fire, the reality is that Jewish towns both inside Gaza and in the surrounding areas came under attack repeatedly before the disengagement. The first Kassam missile was fired from Gaza in 2001. Much higher casualties – civilian and military – were sustained before the disengagement than after. Fewer than 9,000 Jews lived in the midsts of over a million Palestinians who violently opposed their very existence. Expecting the IDF to protect them over time was unreasonable.Israel also reaped some diplomatic gains from the pullout.Perhaps the most significant was then-US president George Bush’s 2004 letter, endorsed by overwhelming majorities by both houses of Congress. Large settlement blocs in Judea and Samaria would remain an integral part of Israel in any two-state solution and Palestinian refugees would be settled in a future Palestinian state, not in Israel.The letter marked a major shift in American policy that had traditionally seen settlements as an obstacle to peace.But perhaps the biggest lesson to learn from the disengagement is also its biggest flaw: the pullout proved once and for all the utter folly of unilateral territorial concessions.The scenario played out following the IDF’s 2000 unilateral pullout from South Lebanon brought about the rise of Hezbollah, which repeated itself in Gaza. Less than two years after Israel evacuated the Strip, Hamas, in a bloody coup, ousted Fatah and seized control.This is in large part because the pullout was seen, at least in the eyes of Palestinians, as the result of the success of Hamas’s terrorism and rocket fire. Where negotiations had failed to achieve territorial concessions, argued Hamas supporters convincingly, violent struggle had succeeded.Hamas’s success in smuggling into Gaza larger and more deadly rockets, with increasingly longer range, taught Israel the importance of maintaining control over borders in any future territorial concession to Palestinians. The same lesson can be learned from the Sinai Peninsula – returned to Egypt as part of the Camp David Accords – which has under Egyptian control deteriorated into anarchy and been overrun by violent Beduin tribes and groups connected with al-Qaeda and Islamic State.This has informed Israel’s insistence on maintaining control over the Jordan Valley as a condition for granting Palestinians more territorial autonomy on the West Bank.Israel does not want a rerun of South Lebanon, Gaza, or Sinai on the West Bank.Though public opinion has shifted over the past decade since the 2005 pullout from Gaza and northern Samaria, it is wrong to claim that the disengagement was a complete failure. But perhaps the most important lesson to be learned from the disengagement is the potential danger of territorial concessions.Any future two-state solution must be reached through direct negotiations with the Palestinians and must include iron-clad security arrangements. We must keep this in mind as we mark a decade since the disengagement.