One year ago, Hamas killed some 1,200 people - overwhelmingly civilians - in Israel and took more than 250 hostage. Since then, Israel has reduced much of Gaza to rubble; more than 40,000 of its inhabitants reportedly have been killed, a figure that includes 10,000-20,000 Hamas militants. Over 700 Israeli soldiers have lost their lives fighting Hamas and other Iranian-backed proxies.

The conflict is obviously far from over. Rarely a day goes by without new military strikes and casualties. That said, the most intense phase of the Gaza conflict seems to be winding down: with Hamas degraded militarily, Israeli leaders have shifted their focus north, attacking Hezbollah's leaders and assets in Lebanon. It is not too soon, therefore, to attempt to summarize and assess the lessons and legacy of October 7.

For starters, assumptions can be dangerous. The attack surprised Israel for the second time in its history (the first being the launch of the 1973 October War). Although there were warnings about what Hamas was planning, senior military and political officials did not take them seriously. They continued to station most of the Israel Defense Forces' battalions in the West Bank, leaving the border with Gaza nearly unprotected. And as was the case 50 years earlier, complacency proved to be costly.

The October 7 attack also demonstrated that the enemy of your enemy is not necessarily your friend. For a decade, the Israeli government under the direction of Prime Minister Binyamin Netanyahu provided substantial economic support to Hamas with the explicit hope that doing so would better position Hamas to compete with the Palestinian Authority (PA). Netanyahu's goal was to divide Palestinians, weaken the influence of the more internationally palatable voice of Palestinian nationalism, and thereby render a two-state solution impossible.

Israel succeeded all too well in contributing to the weakening of the PA. Where it failed was in thinking it could buy off Hamas.

Wars are as much political as military undertakings. It is possible to win a war on the battlefield and still lose it. Israel has done precisely that in Gaza, by choosing to fight a conventional war against an unconventional foe without a plan for what comes next. Military success must be translated into enduring security and governance arrangements. But Israeli officials have refused to advance a proposal for either, fearing that a viable plan would require a role for the PA, along with an Arab stabilization force, which would build momentum toward a Palestinian state and catalyze Israeli infighting that could topple Netanyahu's government.

Making matters worse, Israel is defining success - the eradication of Hamas - in terms that cannot be met. Israel thus loses by not winning, whereas Hamas wins by not losing. Hamas, which is as much an idea and a network as an organization, will inevitably survive in some form and retain the ability to reconstitute itself, especially in the emerging context of an open-ended Israeli occupation with no competition from more moderate Palestinians.

What has happened since October 7 also offers some lessons for would-be mediators. Persuasion alone cannot be relied upon to change the behavior of others, be they friends or enemies. Diplomacy must be backed by incentives and sanctions, and sometimes carrots and sticks ought to be abandoned.

Moreover, diplomacy cannot succeed if the mediator wants success more than the protagonists, who must conclude for themselves that compromise and agreement are preferable to continued conflict. When the protagonists conclude otherwise, no amount of mediation, no matter how well-intentioned, can succeed.

The legacy - or more accurately legacies - of October 7 provide little ground for optimism. A two-state solution is more distant than ever. Such an approach was already a long shot before October 7, but the last year has reinforced Israelis' doubt about the desirability and possibility of living safely alongside an independent Palestinian state. At the same time, Israel's response to October 7 has strengthened anti-Israel views among Palestinians in Gaza, the West Bank, and Israel proper, and strengthened the appeal of Hamas, which, like its backers in Iran, has no interest in peaceful coexistence with Israel.

The net result is that the future is likely to resemble a "one-state non-solution": Israeli control of the territory between the Mediterranean Sea and the Jordan River, an expanding settler population, and frequent clashes between Israeli security forces and Hamas in Gaza and with Hamas-like militias in the West Bank.

Israel has lost a great deal, not just in lives and economic output, but in reputation and standing in the United States and the world. A younger generation sees Israel more as Goliath than David, more oppressor than oppressed. Anti-Semitism has spiked. And with prospects for a two-state solution all but dead, Israel could well face a binary choice between being a Jewish state and a democratic one. The weakening of Hezbollah and the Houthis, however welcome, does not alter these realities.

Israel has also paid a price in the region. Iran has achieved what may have been one of its original goals for the attack: making it more difficult for Saudi Arabia, a powerful force in the Arab and Islamic worlds, to establish formal diplomatic relations with Israel. Although condemnation of Israel's actions since October 7 will not prevent intelligence and military cooperation with select Arab governments facing the mutual threat of Iran, the kingdom's ruler has walked back his openness to normalizing relations in the absence of an independent Palestinian state.

The US has also paid a high price since October 7. It has lost standing in the Arab world for its inability to influence Israeli policy, and has alienated some in Israel with its criticism and independent moves. Moreover, the US finds itself once again deeply involved in the Middle East when its strategic priorities are to deter Chinese aggression in the Asia-Pacific and counter Russian aggression in Europe. All this no doubt brings satisfaction to the anti-Western axis comprising China, Russia, North Korea, and Iran.

None of this was inevitable. Successive Israeli governments chose to weaken the PA and underestimated the threat posed by Hamas, which took advantage by staging its brutal attack. Israel then responded militarily and not at all politically. And the US expended most of its diplomatic capital advocating in vain for a ceasefire that neither protagonist wanted. The human, economic, and diplomatic price has been enormous, and what already was the world's most troubled region has been left even worse off.

From Project Syndicate