Will Biden get an Israel-Hamas ceasefire before the end of his term? Probably not, sources say

President Biden's months-long effort to broker a cease-fire between Israel and Hamas has once again encountered a serious obstacle.

U.S. officials are reassessing their approach after Hamas introduced a new demand, complicating negotiations that were already teetering.

In recent weeks, U.S. negotiators, along with representatives from Qatar and Egypt, believed they were on the verge of presenting both sides with a final "take it or leave it" proposal.

But those hopes were dashed when Hamas changed the game- insisting that civilian hostages also be exchanged for long-term prisoners and complicating a prior tentative agreement in which only soldiers would be traded for militants. One senior U.S. official called the new condition a "poison pill."

The delay is the latest setback in a grueling process that has dominated Biden’s foreign policy agenda for the better part of a year. His administration has been striving for a cease-fire that would not only end the violence in Gaza but also avoid a broader regional conflict. However, with the clock ticking down on his presidency, the chances of achieving peace before he leaves office appear increasingly slim.

The breakdown in talks has intensified pressure on both the U.S. and Israeli governments. In Israel, tensions have boiled over after the IDF recovered the bodies of six hostages, executed by their Hamas captors in Gaza.

This discovery sparked widespread protests against Prime Minister Benjamin Netanyahu, who many in Israel believe has not done enough to secure the hostages’ release.

For months, the families of the remaining hostages have accused Netanyahu of stalling, and new demands from both sides have repeatedly upended negotiations.

At various points, the administration believed a cease-fire was within reach, but each time, the talks were derailed by either Israeli or Hamas demands that set negotiators back by weeks, if not months.

Inside the Biden administration, frustration is mounting. Some officials believe that the president should apply more pressure on Netanyahu, who has been accused of stalling the talks. However, a public rebuke is seen as less likely following Hamas’s execution of the six hostages (which included Israeli-American Hersch Goldberg-Polin), which U.S. officials believe has made the Israeli prime minister even more cautious about moving forward.

While Biden’s team is still pushing for a cease-fire, many U.S. officials fear that neither Israel nor Hamas is sufficiently motivated to reach an agreement.

* The Washington Post contributed to this article.