What comes next after Hamas leader Yahya Sinwar’s death?

Biden administration officials are celebrating the death of Hamas leader Yahya Sinwar at the hands of Israel Defense Forces as a triumph of justice over evil, but also as a key opportunity to settle the war in Gaza by relaunching negotiations aimed at securing a cease-fire and the release of the remaining hostages in the enclave.

But even though American diplomats say Sinwar's demise removes a major obstacle to peace, they acknowledge mediators still face a challenging road ahead.

ABC News spoke with officials and analysts about whether Sinwar's killing could mark the beginning of the end of the conflict in Gaza and what's next for the Middle East at large.

A power vacuum in Gaza

Hamas confirmed the death of Sinwar on Friday but vowed to fight on in his absence—restating its position that no hostages will be freed until there is a cease-fire in Gaza and all Israeli troops are withdrawn from the enclave.

Whether the militant group stands by that could depend on who ultimately replaces Sinwar, but experts said there is also an opportunity to be found in the uncertainty rippling its ranks.

"The chaos within Hamas following Sinwar's death may provide a chance to exploit uncertainties and divisions to expedite the release of the remaining Israeli hostages and the implementation of a general stand-down and demobilization within Hamas," Ahmed Fouad Alkhatib, a resident senior fellow with the Scowcroft Middle East Security Initiative, told ABC News.

"Israel, Arab nations and the United States should now offer mass amnesty for remaining Hamas members who lay down their arms and stop fighting," he added. "They should also offer financial rewards to those who either turn in Israeli hostages or provide information leading to the whereabouts of remaining abductees."

Jon B. Alterman, the director of the Center for Strategic and International Studies' Middle East Program, also sees possibility arising from the tumult, but notes that Hamas' disorder will complicate efforts for diplomacy in the short-term.

"The war in Gaza is not over, but it has moved to a new phase. Hamas will be fractured as a fighting force, and some groups within Hamas are likely to want to double down on violence while others may seek to preserve options for the future," he said.

"Sinwar seemed strongly opposed to compromise, so his death makes some sort of settlement more possible. At the same time, the lack of a single credible Hamas leader means it will be hard to push some parts of the organization toward a cease-fire," Alterman said.

U.S. officials expect it will take days, if not weeks, for mediators to fully diplomatically reengage with Hamas as the group sorts out its internal affairs but say that who ultimately is selected as Sinwar's successor could be telling.

If Sinwar is replaced by his brother and righthand man, Mohammed, they expect the group will attempt to stand by its hardline positions. However, officials believe the elevation of a high-ranking official within Hamas' political wing could be a favorable sign for the future of negotiations.

What does Netanyahu do next?

Of course, implementing a cease-fire deal in Gaza requires securing not only Hamas' cooperation, but the Israeli government's as well.

In an address to Israel following the news of Sinwar's death, Israeli Prime Minister Benjamin Netanyahu declared that his country had shown the world "the victory of good over evil" but said the war "is not over yet."

Communications between the U.S. and Israel were largely celebratory in the aftermath of Sinwar's killing, but officials said President Joe Biden did lay the groundwork for what's expected to be a strong push by the administration to convince Israel to focus on what it commonly calls "the day after" the conflict in Gaza during his call with Netanyahu on Thursday.

Secretary of State Antony Blinken is also expected to make a hard sell to Israeli officials when he journeys to the Middle East in the coming days and the State Department has promised to push the country's leadership to make the "tough decisions" required to reach a pact to end the war in Gaza.

But whether Netanyahu sees the benefits of such a deal remains to be seen.

Ghaith al-Omari, a senior fellow at the Washington Institute for Near East Policy, described Netanyahu's comments in the wake of Sinwar's killing as "conflicting messages" and argued the ambiguity might jeopardize the return of the captives.

"Unless there is clarity from Israel right now, while things are still hot, we might miss this opportunity," he said.

A "political initiative" – including a cease-fire in Gaza, return of the hostages, and the beginning of post-war talks – has the support of "key constituencies" in Israel, including the military establishment, al-Omari said. Yet hardliners believe Israel should press its advantage in Gaza and continue military operations with Sinwar dead and the terrorist organization weakened.

According to al-Omari, the Biden administration's outspoken optimism about the prospects of a cease-fire deal at this pivotal moment is—at least in part—a play to encourage Netanyahu to embrace diplomacy.

"What they're trying to do is to indirectly apply pressure on Bibi by saying that this is the moment to go for it. It becomes harder for Bibi to say, 'You know what? I'm not going to do anything,'" he said. "So this is the administration's way, in addition to what's happening behind closed doors, to publicly create a narrative that puts pressure on Netanyahu."

But still, Alterman argues that Sinwar's demise gives Netanyahu a level of political armor.

"In the immediate term, Sinwar's death is a massive victory for Netanyahu. It is a huge 'I told you so' to people who were arguing he should have taken a hostage and cease-fire deal with Sinwar over the summer," he said. "He has been politically resurrected, and Sinwar's killing will now be held up as his greatest triumph."

Iran's web of proxies

The death of the Hamas leader comes as Israel is preparing to launch a counterattack against the group's main sponsor, Iran, and as it is intensifying its campaign in Lebanon against another of its powerful proxies, Hezbollah.

Jonathan Panikoff, the director of the Atlantic Council's Scowcroft Middle East Security Initiative and a former U.S. deputy national intelligence officer for the Near East, says that while Sinwar's death might present a chance "to close one of the most painful chapters in Israel's recent history," it will do little to resolve the country's other regional conflicts.

"Israel's operations in Lebanon have already begun and are not likely to stop, no matter the result in Gaza," he said, adding that the Israel Defense Forces will want to charge ahead with its mission of "eliminating Hezbollah's cache of its most lethal weapons, such as ballistic and cruise missiles."

Panikoff also argues that Israel is likely still just as determined to hit back at Iran with a military strike the Biden administration says that—while justified—may prompt further escalation.

"Sinwar's death almost certainly won't prompt Israel to reverse course and decline to strike Iran in retaliation for its ballistic missile attack on Oct. 1, even if it comes as new negotiations are underway for a deal in Gaza. The necessity to ensure deterrence is reestablished has never been of greater importance to Israel," he said.