CNN
—

For months, frustrated American officials eager to end the war in Gaza have quietly pondered the one scenario that they believed could loosen stalled ceasefire talks: the death of Hamas leader Yahya Sinwar, believed to be deep beneath Gaza Tunnel network hidden by the group.

Whether this will be the case in the coming days remains to be seen. Without his unique operational control, the group's constellation of commanders, believed to be holding dozens of Israeli hostages in the Hamas tunnels, could be left to fend for themselves and pursue a new approach.

How and with whom to reach a hostage-taking and cease-fire agreement is now a matter of uncertainty for American officials, who spent the hours after Sinwar's death trying to figure out whether he had a successor.

Secretary of State Antony Blinken said in August that “the fate of the deal” — regarding the ceasefire and hostage agreement between Israel and Hamas — was in Sinwar’s hands. But U.S. officials did not say Thursday that his death would lead to a deal overnight.

“We don’t know what that means yet,” a U.S. official said, adding that there could be “rapid” progress toward a ceasefire and hostage-taking agreement or “there could still be a long way to go.”

“It would help a lot to portray this realistically,” said a second senior US official, referring to Sinwar’s death.

Despite all the uncertainties, this moment was seen as significant in the White House and throughout the Biden administration.

Sinwar's killing, perhaps more than anything else, is the singular event that many U.S. officials have called the biggest potential turning point in the Israel-Hamas war. Weeks before the American presidential election, the death has the potential to change a conflict that long ago weighed on the political fortunes of President Joe Biden and, by extension, Vice President Kamala Harris' campaign.

Even after Sinwar's death, there is virtually no expectation that the broader Middle East conflict will be resolved before Election Day, especially as Israel prepares to retaliate against Iran's ballistic missile attack earlier this month. Negative views of the conflict have deepened among many voters after a year of fighting. Still, any development that could lower regional temperatures would be welcome, both at the White House and at Harris' campaign headquarters.

As progress toward a ceasefire agreement to end the war had remained stubbornly stalled for months, senior government officials had clung to the hope that Sinwar could one day be eliminated – opening doors in the talks that simply would not have been accessible otherwise.

While progress toward a hostage ceasefire agreement to end the war remained stubbornly stalled for months, senior government officials had held onto hope that Sinwar could one day be eliminated – opening doors in the talks that otherwise simply would not have been accessible would be.

“Everything depends on Sinwar,” a senior government official put it bluntly earlier this year as ceasefire talks stalled.

To be sure, Israeli Prime Minister Benjamin Netanyahu had put up a number of hurdles to a hostage deal, causing enormous frustration in the White House. But the Israeli leader had publicly stated that he would pursue Sinwar until his death. Simply put, U.S. officials viewed Sinwar as the scalp Israel most needed to declare it was done with the Hamas war.

“Sinwar’s death would give President Biden another opportunity to push again for the implementation of the first phase of the ceasefire agreement, and it would increase pressure on Netanyahu to do so,” said Jonathan Panikoff, a former senior intelligence analyst specializing in the region . “For months, Israel has stressed that Sinwar is the sticking point, that he doesn't want a deal and is constantly changing prisoners' demands in exchange for hostages. But at the same time there was a lot of talk that much of Hamas was exhausted and would welcome a reprieve.”

“Whether an agreement to cease hostilities can be reached will depend on the new leader, but at least it provides space and an opportunity that has not been seen in several months,” Panikoff said.

The ongoing military conflict between Hezbollah and Israel complicates any potential possibility of ending the sprawling conflict, a US official said. The US regularly shares intelligence with Israel to determine Sinwar's whereabouts. However, it is not clear whether this intelligence contributed to this particular operation.

“The IDF is more surprised about this than we are,” the official said, noting that the Israelis had told them it was not an operation they carried out specifically against Sinwar.

In recent months, American assessments have increasingly concluded that Sinwar was self-absorbed, fatalistic about his chances of survival and determined to continue to bog Israel down in a military conflict that has tarnished its international reputation.

That mindset had only solidified as the Gaza war reached its one-year mark earlier this month, leaving American officials doubtful that Sinwar would ever agree to a hostage-taking and ceasefire agreement.

With his death, the path forward is not immediately clear.

“This is a large rock thrown into a lake and the waves are quite extraordinary,” said Aaron David Miller, a veteran Middle East negotiator who has worked for several American governments, adding: “Will this be a… “Provide a political explanation and justification for Benjamin?” Should Netanyahu seriously consider working together to try to de-escalate and ultimately end the war in Gaza? These questions are currently unanswerable, but the implications are very clear.”

Among the questions American officials are now seeking answers to is who will make military decisions for Hamas. Sinwar had ordered his commanders to kill their hostages if they were besieged by Israeli forces, an order that was not clear would be renewed.

“If you actually talk about negotiations now, if there is a Palestinian negotiator on the side of Hamas who now understands that negotiations are the only way out if the organization is to survive in any way, then you may have an …” opening. But you have inertia and you have to keep looking for hostages,” Miller said. “I don't think the Israeli government's position will immediately shift to 'let's stop shooting and now let's start talking'.”

Sinwar has long lived in deep isolation, often making it difficult for Qatari and Egyptian mediators to reach him as they worked to negotiate a ceasefire agreement.

U.S. officials believed he no longer used electrical communications devices and relied on human sources to transmit and receive information. For long stretches, American officials couldn't even say with certainty whether he was alive or dead.

“By all accounts, Sinwar was the biggest obstacle within Hamas to a ceasefire and hostage release agreement in Gaza. Depending on who would take his place, Sinwar's death could revive hopes for an agreement to end the war. “That assumes, of course, that Netanyahu is willing to make a deal while his coalition talks openly about restoring Israeli settlements in the area,” said Andrew Miller, a former senior State Department official who covers Middle East issues.

Biden had tried in talks with his Israeli counterpart to promote an end to the war in Gaza, which did not rule out operations to find and kill Sinwar.

“Looking back, I wish I could have convinced the Israelis of a lot of things,” Biden said at a news conference in July. “But the bottom line is that we now have a chance. It's time to end this war. This does not mean that we have to turn away from the persecution of Sinwar and Hamas.”

But while operations in Gaza slowed as Israel focused on its northern front with Hezbollah in Lebanon, deadly airstrikes continued, leading to a rise in the civilian death toll. As the US election approaches, the government has begun putting new pressure on Israel to improve humanitarian conditions in the Gaza Strip, which have deteriorated significantly in recent weeks.

In a stern letter released this week, Blinken and Defense Secretary Lloyd Austin warned Israel that failure to deliver further aid to the enclave could lead to a cessation of military aid.

How the conflict will develop in the three weeks before Election Day remains one of the biggest uncertainties for the two presidential campaigns. Although the crisis is not a priority issue for many voters, it has complicated Harris' efforts to win Michigan, a state with a large concentration of Arab-American voters. She's campaigning in the state for three days this week.