Hostilities have reignited in the Gaza Strip following the collapse of a seven-day truce between Israel and Hamas. 

This development has shattered the immediate extension of a ceasefire, a goal pursued by the U.S., Israel's biggest ally in the war. On the horizon looms the inception of Israel's offensive into the southern part of the Palestinian territory, a prospect that is sure to pose further challenges for Washington.

The Biden administration has been facing mounting pressure at home and abroad as Israel's military campaign, triggered by Hamas' October 7 attack, has killed thousands of Palestinian civilians and reduced much of the coastal enclave to rubble, contributing to a humanitarian catastrophe that has raised global concern.

While the delivery of humanitarian aid to Gaza during the truce brought some solace to those suffering from a severe shortage of food and water, a relief effort in which Washington played a facilitating role, it now faces the urgent task of restraining Israel from further exacerbating the dire situation in the next phase of its offensive.

With southern Gaza even more densely populated now after the war drove a vast majority to flee from the north, the Biden administration has stepped up its warnings to Israel, urging it to "carefully think through" the manner of its offensive and do its best to limit displacement, according to U.S. media reports. Though Israel's response was reportedly "receptive," conundrums faced by its government are making it hard to follow U.S. requests.

On the Israeli right, the ceasefire that has allowed Hamas to regroup was greeted with deep frustration, and calls for an intensified campaign to target the Islamist group are mounting on Prime Minister Benjamin Netanyahu's government, which has already been reeling from its failure to prevent the deadliest single incident in Israel's 75-year-old history.

Netanyahu, who has been focusing his struggle for political survival on appealing to the right, is offered little option but to adopt a tough stance, meaning a potential return to his government's apparent disregard for the destruction of entire residential blocks. In the wake of the truce, the Israeli military has dropped leaflets on a southern Gazan city telling civilians to evacuate further south – to the crowded town of Rafah on the Egyptian border. This indicates an intensifying round of air strikes on an area that had been relatively left alone, as well as a possible expansion of Israel's ground offensive.

On top of that, the week-old window that had been opened for Hamas' short recovery is weighing down Israel's ability to realize its stated goal of eliminating the group, which poses additional challenges for its army to avoid civilian casualties. 

Military experts say Hamas likely took the opportunity to refurnish its arsenal, restore chains of command and switch tactical positions. That created more room for maneuver for the militant group to sustain its alleged tactic of sheltering below hospitals and schools, a ploy that can keep Israel's indiscriminate air bombardment under global scrutiny.

On the other hand, Israel had equal time to repair its own damaged machinery and reevaluate its military strategies, which might have focused on how to effectively cripple Hamas’ underground tunnels, a key asset for the group to undermine the morale of Israeli troops, and did not exclude discussions on the minimization of civilian deaths.

To keep supporting Israel with massive military aid – a practice the U.S. has upheld by funneling tens of billions of dollars in weapons over the past 70 years – it would have to bear the burden of contributing to the devastation inflicted on the Palestinian territory, which has drawn growing criticism from the American left and the international community. The reputational damage to the Biden administration is testing its patience for Israel, something that had reportedly run thin even before the truce.

Nonetheless, it has so far remained unwavering in keeping the faucet on. Earlier this week, national security adviser Jake Sullivan reportedly defused a belief that the administration plans to place conditions on its military assistance to Israel – the White House has requested a $14.3 billion package for Israel's war effort – even though some Democratic lawmakers insisted on conditionality. Analysts suggest that the maximum public support the U.S. is offering is designed to create more leeway for it to pressure Israel behind the scenes.

For Israel, a key facet of U.S. backing has been its diplomatic maneuvering in the Middle East, to which Secretary of State Antony Blinken has made trips aiming to appease regional allies. It has offered room for Israel to maintain its freedom of action, which is supported also by an antipathy towards both Hamas and other Iran-backed militant groups across the region.

But as anger over the rising civilian death toll mounts, Washington's vision of roping in regional powers for a future peace settlement in Gaza faces the potential of paralysis – Arab nations have already rejected the idea of forming a force to secure post-war Gaza. In the meantime, Israel's suggestion of creating a buffer zone following the war has deepened its neighbors' fears that Palestinians would be squeezed out of the enclave, making it more difficult for the U.S. to reconcile a plan with its allies.

What the U.S. can otherwise achieve in its mediation efforts is the potential restart of a ceasefire, which would allow more humanitarian relief to reach the embattled territory while paving the way for further releases of Israeli hostages held by Hamas, one of the key objectives for Israel's ground operation. 

While the Netanyahu government said on Saturday that it had recalled its team of negotiators from Qatar, a key mediator in the conflict, U.S. diplomats are still working to extend the collapsed truce, something that Israel is obliged to consider as long as the freeing of hostages is guaranteed.

Other roles that Washington can successfully play are limited, as the domestic realities within both Israel and Arab nations are rendering any compromise uncertain. And as the U.S. is edging closer to next year's elections – younger and more progressive Democratic voters detest their government's support for Israel – Biden's Israel dilemmas will only grow.