Yahya Sinwar, Oct. 7 mastermind, was killed in Gaza. What now?

The death of Hamas leader Yahya Sinwar provides a unique chance for Israel to retrieve its remaining hostages. It also offers the possibility of ending the Gaza war in a way that secures the Jewish state, while also ending the humanitarian catastrophe that has engulfed Palestinian civilians.

But that opportunity must be seized quickly — or it is likely to vanish.

If it’s missed, Israel looks set to sink into the quagmire of a long-term occupation and Jewish resettlement of northern Gaza. This, in turn could spur the rise of a new variant of Hamas among bitter Gazans.

Which direction the conflict takes will depend on whether Prime Minister Benjamin Netanyahu sticks to the war-only option, even though Hamas is now seriously broken, or finally turns to a cease-fire-for-hostages deal that could be imposed on weakened Hamas leaders. The United States, the Europeans, and moderate Arab countries are ready to help with the latter.

This moment should not be squandered.

» READ MORE: One year after the Oct. 7 Hamas massacre, hostage families feel betrayed | Trudy Rubin

Sinwar, who was killed Wednesday after a firefight with Israeli military forces, had organized the murderous Oct. 7 attack on Israel that slaughtered 1,200 people, mostly civilians, and took 250 hostages. He was a psychopath who ruled Gaza through charisma and a fearsome reputation for personally killing opponents.

An Israeli intelligence officer — who got to know the Hamas leader while Sinwar was imprisoned in 1988, before being released as part of a prisoner exchange in 2011 — recalled a chilling response to a question about Palestinian suffering caused by Israel’s response to Hamas terror attacks.

“I asked [Sinwar] is it worth 10,000 innocent Gazans dying and he said even 100,000 is worth it,” Yuval Biton told the Israeli newspaper Haaretz.

The question is what happens to Gaza now that Sinwar’s gone.

“His death can change a lot, or the moment can be wasted as previous ones were wasted,” I was told by phone from Jerusalem by the Israel Policy Forum’s Nimrod Novik, a member of the executive committee of Commanders for Israel’s Security and a shrewd security expert.

Indeed, it is startling how many previous opportunities to crush Hamas have been wasted. In the 1980s, the Israeli government encouraged the development of Hamas in Gaza because they saw the Islamist group as a check on Yasser Arafat’s secular Fatah Party.

For more than a decade until shortly before Oct. 7, Netanyahu permitted officials from Qatar to carry millions of dollars in cash into Hamas in Gaza because he thought he could buy off the Islamists. Meantime, Netanyahu undermined secular Fatah on the West Bank, whose police force detested and combated Hamas members.

Netanyahu’s contradictory behavior had a purpose. Fatah had accepted the principle of two states, Israeli and Palestinian side by side, while Hamas’ ideology called for the destruction of Israel. So undercutting Fatah and financing Hamas meant there would be no further Israeli-Palestinian peace process.

That fatally mistaken strategy continued until Oct. 7.

Now, says Novik, there is a moment for Israel to change course dramatically and get back to the strategic track. “Here is an opportunity that a reasonable Israeli leadership would leverage to declare victory and move on. If you fight on until you kill the last Hamas operative, the war will last for decades.

“Sinwar’s death serves symbolic, emotional, and revenge purposes,” Novik continued, “and we should use the victory before Hamas gets its act together.”

» READ MORE: After beheading Hezbollah, it’s time for a cease-fire, not an Israeli invasion | Trudy Rubin

Israeli security experts believe Sinwar probably had a succession plan. But none of the potential candidates — either within Gaza or in Qatar — can possibly match his stature. Especially given that he had concentrated power in his hands and instilled such fear.

What Novik and other security experts propose is that Netanyahu finally go for an agreement that exchanges a cease-fire for the hostages. To increase Palestinian public pressure for such a deal, the Gaza Strip could be blanketed with pamphlets saying this is the only way to end the war.

The Biden administration, along with Egypt and Qatar, have previously put forward proposals to carry out such a deal in three stages; with Hamas seriously weakened, Arab pressure on Hamas can be intensified. Such a deal could draw in a multinational Arab force to help police Gaza. Egypt and the Saudis could help set up a temporary Gazan leadership that does not include Hamas but draws in and strengthens members of the Fatah-led Palestinian Authority on the West Bank. With Sinwar gone, local Gazans might be less afraid to join.

To draw in Arab support for peacekeeping, and for financing rebuilding Gaza, however, such a deal would have to lay out a horizon for Palestinian self-determination. And here’s where we come to the crossroads where Netanyahu must make a critical choice between two very divergent paths.

Option One: He can choose an open-ended Israeli occupation of Gaza. This is being urged on him by his extreme-right cabinet ministers — Bezalel Smotrich, the effective civilian governor of the West Bank, and Itamar Ben Gvir, the Interior minister. Both Smotrich and Ben Gvir are aggressively encouraging Jewish resettlement of Gaza, and a permanent Israeli military presence. They are organizing rallies calling for Jewish settlements, dismantled in 2005, to be rebuilt in Gaza’s north.

These messianic ministers make clear they want to make life so impossible for Gazans that they are compelled to leave the strip or are physically forced out. Both men maneuvered a total blockage of food deliveries to northern Gaza for two weeks, which caused such catastrophe that the Biden administration had to threaten a military aid cutoff if the situation wasn’t rectified over the next 30 days.

That path is guaranteed to breed a Hamas 2.0 embraced by young Palestinians who are offered no other future. It is also guaranteed to spark a greater explosion on the West Bank as Smotrich and Ben Gvir encourage violent Jewish settlers who attack Palestinian farms and villages.

Down that path lies further international isolation, continued bloodshed, and the death of most or all of the hostages. And I haven’t even gotten to the situation in Lebanon or Israel’s understandable response to Iranian missiles. This option will waste a chance to build on Hamas’ crisis to isolate its allies, Hezbollah and Tehran.

Option two: Taking advantage of Sinwar’s death, Israel could make a safe exit from Gaza. It would also offer Gazans an alternative to Hamas, which will encourage them to reject the extremist ideologues. Furthermore, it is the best way to build a solid regional Arab-Israeli opposition to Iran — and the only way to achieve normalization with Saudi Arabia.

I listened to Netanyahu’s speech Thursday about Sinwar’s death. Despite pledging to return the hostages, he seemed headed toward Option One — meaning endless war in Gaza.

Perhaps that’s because, as his critics argue, the Israeli leader is afraid he will face prison time for corruption if the wars stop. If so, he will have wasted this phenomenal chance to build on Sinwar’s death to secure Israel in coming decades.