Last Tuesday, Israel’s military approved a plan to invade Lebanon to fight its dominant militia, Hezbollah. Hezbollah’s leader issued his strongest threats against Israel in years the following day. And the U.S., Israel’s most powerful ally, has indicated that it will not block an Israeli offensive.

That’s just the past week. Over the nine months prior, more than 150,000 people on either side of the Israeli-Lebanese border have fled their homes as alternating rounds of Hezbollah rockets and Israeli airstrikes have steadily expanded. The attacks have extended beyond the two sides’ border combat facilities, killing nearly 100 Lebanese civilians and 10 Israeli civilians, rendering southern Lebanon “uninhabitable” and striking journalists, the U.S.-backed Lebanese military and even Lebanon’s capital of Beirut.

Yet the U.S. and Israel argue they can still avoid a new Middle East war in Lebanon, a conflict that would be catastrophic and worsen regional instability already exacerbated by the Gaza conflict.

In public remarks at the Pentagon on Tuesday, Defense Secretary Lloyd Austin and his Israeli counterpart Yoav Gallant projected hope for U.S.-led attempts at a deal between Israel and Hezbollah that prevents all-out fighting. Negotiations can prevent “terrible consequences,” Austin said, while Gallant spoke of “working closely together to achieve an agreement” that convinces his country and its Lebanese foe to cease hostilities.

The underlying issue is whether Hezbollah maintains its huge presence in southern Lebanon, spitting distance from northern Israel — which violates a United Nations resolution and which Israel sees as an intolerable threat following the Oct. 7 attack that Hezbollah’s ally Hamas, a Palestinian militant group, launched across its border with Gaza, killing nearly 1,200 Israelis, mostly civilians. After Israel initiated its retaliatory campaign into Gaza, Hezbollah began barrages into Israeli territory it cast as in solidarity with Hamas, and Palestinians broadly, as the U.S.-backed Israeli campaign has spurred mass devastation, tens of thousands of civilian deaths and mass hunger and disease. Israel, in turn, presents its strikes within Lebanon as defensive, calling harm to civilians “unintentional.”

The U.S. and Israeli governments claim their current approach bolsters diplomacy because it is linked to a timeline: If conditions in the Gaza Strip ease, Hezbollah may halt its assault and compromise, some U.S. and Israeli officials believe. Israel says it will conclude its large-scale offensive in Gaza within weeks, and on Tuesday, Israeli national security adviser Tzachi Hanegbi linked that possible shift to chances of a bargain for Lebanon.

But for now, the danger of an Israel-Hezbollah war is higher than it has ever been, Biden administration officials and national security experts say — and many insiders are skeptical that President Joe Biden can ultimately avert it.

The core of the concern is the defining theme of Biden’s Middle East policy since Oct. 7: the U.S.’s overwhelming support for Israel.

As Israel’s chief military and diplomatic backer, the U.S. has the most influence of any outside party over its decisions, and is widely perceived as implicated in them. At the same time, it’s Israel that analysts and officials see as more likely to initiate a full-scale war, because Hezbollah has indicated through its statements and relatively measured attacks that it wants to keep the fighting limited.

Such a conflict could rapidly escalate, and if the two sides start pummeling each other and causing huge damage, the U.S. and Hezbollah’s chief supporter, Iran, will face major pressure to get involved. Tehran and Washington already oppose each other’s regional presence, and in Iraq and Syria, U.S. forces and Iran-backed fighters are in close proximity, raising the human stakes of heightened tensions. A top pro-Iran militia in Iraq recently indicated that should Hezbollah face attacks, it would target U.S. interests.

But while Biden may not want the war, his tendencies make it hard to imagine him doing much to prevent it as escalation continues. Since Oct. 7, Biden has repeatedly suggested there will be consequences for Israeli moves and then shown those threats to be hollow. That may have sent a worrying signal to Israel’s decision-makers. Speaking with HuffPost, a State Department official and a Pentagon official working on Middle East issues both compared the U.S.’s opposition to a Lebanon war to the president’s warnings to Israel not to invade the Gazan city of Rafah — which Prime Minister Benjamin Netanyahu largely ignored, forcing a million Palestinians to flee and torpedoing the humanitarian aid infrastructure in the war zone.

“We have let Israel face zero consequences for crossing all of our red lines in Gaza so they are emboldened and know they will face no consequences for going into Lebanon, despite us saying, ‘Don’t go there,’” argued the Defense Department official.

If Israel assumes it has full-tilt American support, it could deem it is best to try to weaken Hezbollah now, while many local civilians are out of the central part of the prospective war zone.

Biden is “pushing to not engage [in a war] but our saying ‘We will support Israel’ I don’t believe is helping,” another State Department official told HuffPost.

Meanwhile, Israel’s fight with Hamas is unlikely to conclude for months or even years, given that the Palestinian faction has retained notable strength, capabilities and support. Should Israel open a so-called northern front with Lebanon, it could seek even greater help from Washington.

“Israel does not have the military capacity to be doing both Hamas and Hezbollah conflicts. I worry that means us sending more resources or in the case of full-out war, intervening for the Israelis,” the second State Department official said.

HuffPost granted anonymity to sources who were not authorized to speak on the record.

A spokesperson for the White House National Security Council argued the administration sees calm along the Israel-Lebanon border as “a top priority” that “must be of the utmost importance for both Lebanon and Israel.”

“We continue to work toward a diplomatic resolution that would allow Israeli and Lebanese citizens to safely return to their homes and live in peace and security,” the spokesperson wrote in an email. “We also continue efforts to secure a deal that would lead to a durable end to the war in Gaza. As President Biden said in his remarks recently, a ceasefire and hostage deal in Gaza will accelerate the possibility of progress, including lasting security and calm along Israel’s northern border with Lebanon. That deal is now with Hamas and the decision is in Hamas’s hands.”

The State Department and the Defense Department did not respond to a request for comment.

U.S. officials have for months worried Israel is stockpiling American weaponry that Biden rushed to deliver after Oct. 7 for an invasion of Lebanon, HuffPost has previously revealed.

During this week’s visit by Gallant, the Israeli minister on Wednesday met with lawmakers and requested “more and faster approvals of arms” that Capitol Hill has a role in approving, a senior congressional aide told HuffPost. “It is hard to view the munitions requests as for anything other than a large-scale bombing campaign of Lebanon, since they have decreased the tempo of air strikes in Gaza,” the aide added.

After this story published, Axios reported that Biden has decided to send Israel a batch of 1,700 bombs from the sole shipment of weapons he suspended over what he had previously described as “indiscriminate bombing” in Gaza. Israel specifically sought those bombs in case of war with Hezbollah, according to the news outlet.

Some in the administration worry the Israelis are trying to manipulate the U.S. side into providing risky military equipment by playing on multiple American fears. Since Oct. 7, Israel has increased pressure on the occupied West Bank, the region seen as the heart of a future Palestinian state — the creation of which the U.S. supports as a regional goal — and the home of the U.S.-backed Palestinian Authority, which American officials see as key to Israeli-Palestinian peace, including in Gaza. The region’s economy has plummeted as Israel has barred 150,000 of its workers from their jobs inside Israel, withheld tax revenues it normally transfers to pay local officials’ salaries and threatened a financial channel that allows the West Bank to trade with the global economy.

Some Biden aides fear a tacit quid pro quo — that the Israelis expect additional arms to help in a Lebanese offensive in exchange for keeping the West Bank afloat — according to the Pentagon official and another U.S. official.

Separately, Gallant has tapped bipartisan American hostility toward Iran, by claiming to legislators that Tehran and Hezbollah may launch a war any moment to destroy Israel, the congressional aide said — while also saying Israel continues to support negotiations with Hezbollah.

Broadly, the Biden administration is currently doubling down on arming Israel. The White House this month recently pushed Democratic lawmakers to permit one of the biggest weapons sales to Israel in years and is considering resuming even the remaining bombs that it had halted over concern for civilians, according to The Washington Post. And Israeli and U.S. officials on Wednesday said the two nations have addressed “bottlenecks” in arms supplies, with an American official telling reporters at a press briefing Washington prioritizes whatever Israel identified as its needs and noting that huge amounts of U.S. weapons continue to currently flow to the country.

Much of the Biden team’s posture reflects its widely criticized ‘bear hug’ strategy since the Hamas-led attack upended regional affairs — an approach that keeps the Israeli government and the U.S. tightly aligned, and rarely involves challenging its unhelpful impulses.

“It’s more critical than ever for the U.S. to lean hard on Israel to realize the mistake a larger campaign would be for their own people, for Lebanon, and for the region. They have tried it multiple times before and it doesn’t yield the results they think it will,” the senior congressional aide said, referring to deadly previous Israeli incursions in 2006 and in the 1980s. “Their experienced national security folks know this but the political leadership ignores it and in fact seeks a broader war.”

While Biden and Netanyahu have become publicly critical of each other, the administration should understand that Israel’s desire for a campaign in Lebanon extends beyond him to many others in Israeli politics, like former general Benny Gantz, whose thinking the U.S. should be seeking to influence, the aide argued.

That’s a product of the overall hawkish shift in Israeli politics and the belief among some Israelis that, in the words of the mayor of a border town hit by Hezbollah, “the choice is between war now or war later” given the growing power of the Lebanese group and its antipathy towards Israel. Attempts by the U.S. and other states wary of Iran to rein in Hezbollah, including by strengthening other powerful forces in Lebanon, have faltered as the country has suffered a years-long economic collapse and political deadlock.

Officials interviewed by HuffPost do not assess war is imminently about to break out, and quiet diplomacy on several tracks, including possible messages between the U.S. and Iran, could still bear fruit. Yet observers note that the longer the tit-for-tat attacks go on and the atmosphere remains extremely tense, the greater the chances are of a miscalculation or shock incident that sparks full-on strife.

The U.S. government has for months been quietly preparing plans for a noncombatant evacuation operation, or NEO, from Lebanon, funneling U.S. citizens and a select group of other civilians to nearby Cyprus, according to the Pentagon official and one of the State Department officials. Canada, Germany, Kuwait and other nations have recently advised their citizens to leave Lebanon, while the U.S. on Thursday reiterated its advice for Americans to reconsider traveling there. The NEO plan is currently “on hold,” according to the Defense Department official.

The fears over Lebanon have exacerbated internal and external disdain for Biden’s Middle East policy, centered on his failure to end the war in Gaza — the root of heightened agitation around the region — and the sense he has disregarded national security expertise, including lessons from past U.S. presidencies.

The Pentagon official spoke of “the consistent fact that brown lives don’t matter to this administration, no matter where those brown people live,” reflecting how frustration among some Biden administration personnel continues to be driven by both strategic reasons and the impression that the president has different levels of concern for different communities.

In recent internal discussions, some U.S. officials have been openly frustrated with colleagues at the White House’s National Security Council, who they feel are only now suggesting information and discussions that were needed weeks or months ago — when risks might have been mitigated, the State Department official told HuffPost.

Randa Slim, a senior fellow at the Middle East Institute think tank who recently spent time in Lebanon, drew a link between the stalled process of establishing a cease-fire in Gaza and the situation in Lebanon.

Though the U.S. is “the only mediator that can provide guarantees” that would enable truces between Israel and its foes in both contexts, for instance by addressing Hamas’ demand for a permanent halt to the Gaza war, “there’s a lot of skepticism about the ability of the U.S. to deliver Netayahu to a deal, particularly as we are in the midst of this ongoing presidential campaign,” Slim said.

Biden “is unwilling to put his foot down like previous American presidents have done at different times with Israeli prime ministers,” she told HuffPost. “The president has enough leverage. So far I don’t think he has opted to use the leverage that will bring Netanyahu to end this.”