The Washington Post reported in a lengthy report that US President Joe Biden's months-long efforts to reach a ceasefire and hostage release agreement between Israel and Hamas have been upended again in recent days, putting the agreement on life support as US officials say they are reassessing the next steps after initially hoping to present a "take it or leave it" proposal to the two sides in the coming days.

The final hurdle, the newspaper claims, is Hamas’s sudden presentation of a new demand regarding prisoners to be released by Israel, which is often frustrating, especially since these efforts have occupied senior American officials, and Biden himself, for nine months. At several recent points, the United States, along with Qatar and Egypt, believed that a deal was within reach, only for Israel or Hamas to derail the talks with new demands that set negotiators back weeks or months.

Overall, Biden’s chances of ending the war in Gaza and bringing the remaining hostages home before he leaves office appear increasingly remote, raising the possibility that he will end his presidency without brokering an end to the conflict that has engulfed his final year in office and threatens to tarnish his legacy.

Negotiators increasingly fear that neither Israel nor Hamas has any real incentive to reach a deal to end the 11-month war. White House officials, lawmakers and diplomats say a cease-fire is key not only to addressing the dire humanitarian situation in Gaza and freeing the remaining hostages, but also to averting a wider regional war, the newspaper reported.

“Most days, it’s clear that the Americans are working harder than the Israeli government on this,” Sen. Chris Murphy (D-Conn.), a senior member of the Senate Foreign Relations Committee, told the paper. “I think [a cease-fire] was not a very likely outcome because of the political calculations that both [Israeli Prime Minister Benjamin] Netanyahu and Hamas were making; I give a lot of credit to the Biden team for persevering and trying to restart and revitalize these talks, even as there were significant obstacles for both sides.”

Earlier this week, as American, Qatari and Egyptian negotiators were working out the final details of a “bridge proposal” aimed at resolving remaining differences between the two sides, Hamas made a new demand that put an agreement out of reach for now, according to a senior administration official who spoke on condition of anonymity to describe the secret talks. The negotiations had already been bogged down by demands Netanyahu made several weeks ago.

The two sides had initially agreed that at some point, Israel would release Palestinian militants serving life sentences in exchange for Hamas releasing Israeli soldiers. But this week, Hamas said civilian hostages would also need to be exchanged for these veteran prisoners, an idea the official called a “poison pill.”

The biggest and most vexing question hanging over the talks, the paper said, is how many of the roughly 100 hostages in Gaza are still alive. Earlier this week, the bodies of six hostages were found, sparking mass demonstrations in Israel against Netanyahu, who many Israelis believe is not doing enough to reach a deal.

US officials believe that a number of the seven remaining American hostages in Gaza are still alive and could be released in the first phase of a three-part deal, according to the senior official, along with a "significant number" of living hostages.

Despite their take-it-or-leave-it concept, Biden administration officials have said they will continue working toward a deal as long as they believe there is a chance, however slim.

Some of Biden’s advisers want him to put more pressure on Netanyahu, whom even Israeli officials have accused of sabotaging the negotiations. There has been debate within the White House about whether to publicly call out Netanyahu as a major obstacle to a deal, but that seems less likely after Hamas executed the six hostages, according to several people familiar with the discussions. In Israel, long-simmering anger toward Netanyahu boiled over this week when the Israel Defense Forces recovered the bodies of the six hostages, who the IDF said were executed by their Hamas captors shortly before their bodies were discovered. At least three of the Israeli hostages, including Israeli-American Hersh Goldberg Polin, were on a list of those to be released in the first phase.

The families of the detainees have accused Netanyahu for months of prioritizing his own political survival over a deal that would bring their loved ones home. Netanyahu upended the talks in late July when he presented a new set of demands, including his insistence that Israeli troops remain on the eight-mile-long border between Gaza and Egypt known as the Philadelphi Corridor.

Israel’s war on Gaza has in many ways consumed the last year of Biden’s presidency, as he has battled privately and publicly with Netanyahu over issues ranging from humanitarian aid to civilian deaths.

Sen. Chris Van Hollen (D-Md.), a member of the Senate Foreign Relations Committee, said the White House has not put enough pressure on Netanyahu. Asked this week whether the Israeli prime minister was doing enough to reach a deal, Biden said, “No.” But Biden has avoided punishing Netanyahu, for example by imposing conditions on military aid to Israel.

“By not criticizing Prime Minister Netanyahu’s intransigence, they have given him political cover to continue stalling,” Van Hollen said. “It’s a mystery to me why the administration doesn’t criticize him more clearly, when the hostages’ families themselves know what an obstacle he has been.”

On October 7, Hamas militants stormed the border fence between Israel and Gaza, killing some 1,200 people, including 311 soldiers, and taking some 250 hostage. Israel immediately launched a retaliatory military offensive on Gaza that has killed more than 40,000 Palestinians, according to the Gaza Health Ministry, and unleashed a humanitarian catastrophe in the territory, including widespread hunger and mass displacement.

The latest setback to the cease-fire talks is the culmination of a process that began almost immediately after a weeklong pause in fighting in late November, which saw an increase in humanitarian aid to Gaza and the release of more than 100 hostages. The administration quickly began working on another deal, one it hoped would last longer and lay the groundwork for a permanent end to the war.

Biden’s impatience with Netanyahu — particularly over Israel’s refusal to allow more humanitarian aid in as northern Gaza was on the verge of starvation — reached a breaking point on April 1, when an Israeli airstrike killed seven aid workers from World Central Kitchen. It crystallized for Biden that Israel had not done enough to protect aid workers in Gaza or alleviate the suffering, according to several people familiar with the president’s thinking.

In a phone call with Netanyahu days after the deadly attack, Biden threatened to reassess the entire U.S. approach to the war if the prime minister did not make immediate changes, including opening a number of ports and crossings to allow more aid in, according to a senior administration official familiar with the call.

Israel made the changes the president demanded, but at about the same time, it carried out an airstrike on the Iranian embassy compound in Syria that killed seven senior members of Iran’s Islamic Revolutionary Guard Corps. American officials were not notified in advance of the attack, prompting the White House to launch an intensive effort to prevent an Iranian attack on American sites and prevent a war between Iran and Israel.

The United States, along with several Arab and European allies, helped thwart an Iranian retaliatory attack on Israel, in which more than 300 missiles and drones were fired. American officials then urged the Israelis not to escalate the situation, according to people familiar with the matter, who spoke on condition of anonymity to disclose confidential discussions.

Ultimately, Israel opted to carry out a small precision strike on an Iranian facility outside the city of Isfahan, telling U.S. officials it would not confirm it publicly until Iran could “save face and de-escalate,” according to a senior administration official.

By May 27, it seemed as if negotiations were back to life.

The Israeli cabinet agreed to a number of Hamas’s demands and proposed linking the first and second phases of the deal. For months, the newspaper reported, Hamas had refused to agree to a deal that did not immediately lead to a permanent ceasefire. Now Israel has proposed that the temporary ceasefire in the first phase will continue as long as the two sides negotiate in good faith about the second phase, which would include a permanent ceasefire and the release of male IDF soldiers in exchange for “higher-value” Palestinian prisoners.

Four days later, on May 31, Biden delivered a speech from the White House laying out the Israeli proposal. The goal, senior administration officials and outside advisers said, was to corner Netanyahu politically and ensure he could not back away from the deal, as well as to build international support and pressure Hamas into reaching an agreement.

On July 2, Hamas agreed for the first time to a gradual proposal that stopped short of a permanent ceasefire. The group had other demands, according to senior officials, but negotiators felt they were getting closer.

All of this was upended on July 27, when Netanyahu issued a series of demands that once again derailed the talks. Chief among them was his insistence that Israeli forces remain along the Philadelphi Corridor, an issue that had not previously been explicitly part of the talks. Days later, Israel carried out an airstrike that killed Hamas leader Ismail Haniyeh in Tehran, which U.S. officials privately condemned as unhelpful to the talks, since Haniyeh had played a key role in the cease-fire negotiations.

The costs of delay are clear. In addition to the six dead hostages, some 4,000 additional Palestinians have been killed since Biden outlined the proposal on May 31, polio has appeared in Gaza for the first time in 25 years, and Gazans have been forced to move to smaller and smaller humanitarian zones where the flow of basic necessities has been halted or sporadic at best.

Inside the White House, the news of the six hostages’ deaths — especially Goldberg Pollin, whose parents, Rachel Goldberg Pollin and John Pollin, were well known to Biden and his top officials, many of whom were in regular text message contact with him as negotiations dragged on — personalized the impact of the failure to reach an agreement. “Anger” and “horror” were among the terms officials used to describe the news of his death.

“The mood was: We don’t have a deal, we now have six dead hostages, and we’re all not doing enough,” a senior administration official said.

Negotiators increasingly fear that a deal is out of reach. Netanyahu has not backed down on his position on the Philadelphi corridor, despite mounting pressure from hundreds of thousands of Israelis who have flooded the streets to protest his position. And even if Netanyahu agrees to the first phase of the deal, negotiators are not confident he will ever accept a second clause that would include a permanent end to the war.

Negotiations with Hamas have also proven cumbersome, U.S. officials said. Its Gaza leader, Yahya Sinwar, is the only one who can sign on behalf of the group, and it remains unclear what his motivations are for reaching a deal.