Danny Danon, Israel’s ambassador to the U.N., directed part of his own comments to the Council at Iran, saying: “This is the last warning. Israel has shown restraint, but from now on you will only see strength. Any further aggression will be met with powerful and swift action.”

The Council meeting was requested by Iran, with the support of Russia and China — close allies of Iran — and Algeria, the only Arab country currently holding a seat at the Council.

Diplomats and senior U.N. officials urged both sides to stand down from the cycle of tit-for-tat attacks, which risk further destabilizing the region and expanding into a regional war.

“Belligerent and threatening rhetoric must cease,” Khaled Khiari, an assistant U.N. secretary general, told the Council. “Both sides must stop testing the limits of each other’s restraint and act in the interest of peace and stability for the region.”

On Saturday, Israel carried out a series of airstrikes on Iran, targeting more than a dozen sensitive sites, including air defense for the capital Tehran, critical energy and oil sites and missile-developing bases. The strikes killed at least four army soldiers who were manning the air defense systems, according to Iran’s military.

The Israeli strikes came in response to an Iranian attack in early October, in which Iran fired nearly 200 ballistic missiles at Israel to avenge the killing of the leaders of two militant groups it backs — Hamas in Gaza and Hezbollah in Lebanon — as well as the killings of Iranian military commanders. Iranian officials have blamed the United States for providing support and assistance to Israel in the wars in Gaza and Lebanon and in attacks on Iran, and Mr. Iravani called Washington “complicit” in the Saturday strikes on Iran.

Linda Thomas-Greenfield, the U.S. ambassador to U.N., denied that accusation. “The United States did not participate in this military operation,” she said, but acknowledged that the United States had “encouraged” Israel to make its retaliation targeted and proportional.

She stressed that the United States did not want the hostilities to escalate any further. “We believe this should be the end of the direct exchange of fire between Israel and Iran,” she said.

In several cities in Iran on Monday, funerals were held for the four soldiers who died in the Israeli attack. Their coffins were draped in Iran’s flag and covered in flowers, with uniformed soldiers serving as pallbearers. Grieving families said the soldiers had lost their lives honorably in the defense of their country, according to video broadcast on state television.

Iran appears to still be assessing the damage from the strikes and publicly downplaying their significance and scope. Iran’s minister of defense, Amir Aziz Nasirzadeh, told Iranian media on Monday that “Israel’s damages were minimal, and we immediately made repairs and replacements.”

At the Security Council on Monday, China and Russia strongly condemned Israel, saying it had violated Iran’s sovereignty and territorial integrity. They joined a chorus of condemnations from countries including Saudi Arabia, Qatar, Egypt and Turkey.

“Israel is trying tooth and nail to draw Iran into confrontation,” Vassily Nebenzia, Russia’s ambassador to the U.N., told the Council. “And Iran is showing exceptional, for such circumstances, restraint.” He accused Israel of violating international law in its attack on Iran and recklessly destabilizing the region.

Iran has been stressing its international backing in the wake of the Israeli strikes. Iran’s foreign minister, Abbas Araghchi, told Iranian media on Monday that his country was pleased with the flow of diplomatic support that followed the attack. He said Iran’s strategy in confronting Israel had two fronts: “diplomacy and the battlefield.”

On Monday, he said on social media that the court’s oversight body had “closed” the matter in May without an investigation because no complaint had been made. He added that the “alleged aggrieved person” had declined the option of an investigation, either internal or external.

Mr. Khan is seeking an inquiry into the accusations against him and how the information was made public, calling the claims “disinformation” and saying news reports about them had breached court confidentiality. He said he had asked that the “inquiry be set up and permitted to do its work without interference” so that the “crucial work” of the prosecutor’s office could continue unimpeded.

But the accusations against Mr. Khan could cast a shadow on his efforts to obtain arrest warrants for the Israeli government’s most prominent figures, an endeavor that some believed was already fraught.

In May, Mr. Khan set off a firestorm of criticism in Israel, the United States and Britain when he sought arrest warrants for Israel’s prime minister, Benjamin Netanyahu, and its defense minister, Yoav Gallant, as well as for Hamas leaders Israel identified as behind the Oct. 7 attack on Israel that ignited the war. Antony Blinken, the U.S. secretary of state, accused the prosecutor of equating Israel with Hamas, which he said was “shameful.”

The three Hamas leaders for whom Mr. Khan sought warrants — Yahya Sinwar, Ismail Haniyeh and Muhammad Deif — have all since been killed by Israel.

Israel has argued in filings to the court that the tribunal does not have jurisdiction over its officials. Separately, it has argued that it has not been given the chance to show that its own institutions can address any accusations internally, as the court’s processes require. Israel, like the United States, is not a party to the statute that created the I.C.C., which has a mandate to investigate and prosecute war crimes and genocide.

On Thursday, Päivi Kaukoranta, the president of the court’s oversight body, the Assembly of States Parties, confirmed that his organization had been made aware of the allegations against Mr. Khan by “a member of his office.” She said that the court “seeks the consent of any alleged victim of misconduct before proceeding with an investigation” but “was not in a position to proceed” with one after its conversation with accusing party.

Ms. Kaukoranta added that “the court has a zero-tolerance policy” when it comes to misconduct, “including sexual harassment, discrimination and abuse of authority,” and that she remained in contact with all parties.

The accusations against Mr. Khan have armed his critics. Some, including the editorial board of The Wall Street Journal, have suggested that the prosecutor rushed his warrant requests in an effort to save his job after the allegations against him were made. Supporters of Mr. Khan, by contrast, say he is now being smeared because he sought the warrants.

Much of the material in the filing has already been widely reported or documented but it also offers new exhibits, according to lawyers close to the case, which throw more light on Gaza’s plight since the deadly Hamas-led Oct. 7 attack on Israel last year and Israel’s continuing military response.

Lawyers familiar with the case said that dozens of researchers and lawyers had worked for months on South Africa’s submission, and that it addressed the razing of most of the Gaza Strip, the suffering and killing of its civilians and the statements made by Israeli political and military leaders about their plans.

South Africa’s filing is meant to remain confidential until oral hearings are held next year, but it will be available to Israel and to the other countries that have joined South Africa’s complaint.

Israel will have several months to challenge the filing in writing. Israel is expected to do, although it has denounced the proceedings as illegitimate.

Included in the new materials submitted to the court is an 827-page report that was made public this weekend by Forensic Architecture, an investigative group based at Goldsmiths, London University, and led by the Israeli-British architect Eyal Weizman.

Called “A Spatial Analysis of the Israeli Military’s Conduct in Gaza since October 2023,” the report says its researchers used multiple methods, including satellite and remote-sensing images, to assess the scale and methods of the destruction in Gaza, including of its medical, religious, civilian and agricultural infrastructure.

The report’s purpose is plain: Its interactive platform is called: “A Cartography of Genocide.”

Lawyers have long explained that genocide is among the most difficult crimes to prove in international law because it requires demonstrating the specific intent to destroy a group, “in whole or in part,” something that Israeli leaders have persistently denied is their intent in Gaza.

But some experts point to a sentence from the United Nations’ genocide convention that forbids “deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part.”

The Forensic Architecture report hews closely to that wording, stating that “our findings indicate that Israel’s military campaign in Gaza is organized, systematic, and intended to destroy conditions of life and life-sustaining infrastructure.”

Months of arguments lie ahead.

The International Court of Justice, which deals with disputes between nations, has been the principal legal venue for denouncing the horrors of Hamas’s deadly Oct. 7 attack and the events in the year since.

South Africa filed its case accusing Israel of genocide late last year. Since then, the court has issued three emergency rulings, warning Israel to avoid genocide and to allow more food and medicine and life essentials into the Gaza Strip and to stop its attacks on civilians. But it has not begun to address the question of whether Israel has violated the U.N.’s genocide convention, which is at the heart of the case.

Israel has criticized UNRWA for decades, arguing that its work aiding Palestinian refugees and their descendants further perpetuated the longstanding territorial conflict with Israel. The Israeli government has accused a handful of the agency’s 13,000 employees in Gaza of participating in the Hamas-led Oct. 7 attacks on Israel last year that triggered the war.

The legislation passed on Monday night had the potential to push the agency’s operations into precarious and uncharted territory.

Israel’s prime minister, Benjamin Netanyahu, is under pressure from Israel’s allies, including the United States, not to move against the agency, and it was unclear how or whether the law would ultimately be implemented.

However, he has consistently excoriated the agency in the past, and hours after the bills passed, his office released a statement that said: “UNRWA workers involved in terrorist activities against Israel must be held accountable. Since avoiding a humanitarian crisis is also essential, sustained humanitarian aid must remain available in Gaza now and in the future.”

The statement continued: “In the 90 days before this legislation takes effect — and after — we stand ready to work with our international partners to ensure Israel continues to facilitate humanitarian aid to civilians in Gaza in a way that does not threaten Israel’s security.”

Several governments including Germany and Spain immediately criticized the passage of the bills. In one example, Prime Minister Keir Starmer of Britain said in a statement he was “gravely concerned,” and he said that the vote threatened the “entire international humanitarian response” in Gaza.

Philippe Lazzarini, UNRWA’s head, said on social media that the move by the Knesset was “unprecedented and sets a dangerous precedent.”

“These bills will only deepen the suffering of Palestinians, especially in Gaza where people have been going through more than a year of sheer hell,” Mr. Lazzarini added.

He also said that the move violated Israel’s obligations under international law, an accusation rejected by Israeli lawmakers.

Under the new legislation, UNRWA would be unable to “operate any representative office, provide any service, or conduct any activity, directly or indirectly, in Israel’s sovereign territory.” They also bar any Israeli government agency from having any contact with UNRWA or those operating on its behalf.

Both bills passed with overwhelming majorities: Each secured over 80 votes in Israel’s 120-member Parliament. Lawmakers from at least two centrist parties joined Mr. Netanyahu’s governing coalition in voting for the measures, reflecting mainstream backing.

Ron Katz, one of the bills’ sponsors and a member of the centrist Yesh Atid party, bluntly equated Hamas and the U.N. agency. “We are saying simply: Israel is breaking away from a terrorist organization, Hamas, which called itself UNRWA,” he said.

For decades, UNRWA has operated schools and clinics in the Israeli-occupied West Bank and in Gaza, as well as some neighboring Arab states, serving Palestinians displaced in the war surrounding the establishment of Israel decades ago. The laws could compel UNRWA to close its office in East Jerusalem, which Israel captured in 1967 and later annexed, a move not recognized by much of the international community.

While the laws’ full consequences are not yet known, UNRWA would struggle to bring in international staff members if Israeli government agencies were barred from giving them employment visas. And it is unclear how the agency would coordinate the movement of its aid workers in Gaza with the Israeli military, even indirectly.

The United States and seven other countries, including Britain, France and Germany, had in recent days urged Israel not to ban UNRWA, arguing that its work was vital, not least for civilians in Gaza. More than 230 of the agency’s staff members have been killed since the start of the war in Gaza over a year ago.

Matthew Miller, the State Department spokesman, said that Secretary of State Antony J. Blinken and Secretary of Defense Lloyd J. Austin III had warned Israel in a letter that “passage of this legislation could have implications under U.S. law.” That missive had threatened a potential weapons cutoff unless Israel took steps to improve the humanitarian situation in Gaza.

“We are deeply concerned by this proposed legislation,” Mr. Miller told reporters on Monday, shortly before the bills were passed. “They really play an irreplaceable role right now in Gaza, where they are on the front lines getting humanitarian assistance to the people who need it.”

“We continue to urge the government of Israel to pause the implementation of this legislation,” Mr. Miller added. “We urge them not to pass it at all. We will consider next steps based on what happens in the days ahead.”

Israel has increasingly worked to block the agency since January, when Israel’s government claimed that 12 of the agency’s 13,000 employees in Gaza had participated in the Oct. 7 attacks. It later added what it said were other cases and argued that scores of the agency’s employees belonged to militant groups. Israel offered little evidence to support this allegation.

In August, U.N. investigators cleared 10 UNRWA employees of taking part in the Oct. 7 attacks, but the U.N. said that nine others were fired because of possible involvement. An independent review in April commissioned by the U.N. found that UNRWA had “a more developed approach to neutrality” than other aid groups and other U.N. agencies.

Aid organizations say that Israeli efforts against UNRWA have weakened humanitarian efforts in the enclave, where the war has displaced most of the population, destroyed public sanitation and the health care system, and made food and potable water scarce. A report by experts this month warned again of famine.

Israeli officials have said that they are acting in compliance with international law and remain committed to providing humanitarian aid to Gaza, but that UNRWA should no longer operate in the enclave.

“UNRWA in Gaza is a rotten tree entirely infected with terrorist operatives,” Oren Marmorstein, a spokesman for the Israeli foreign ministry, said on Monday.

According to numbers released by Israel’s foreign ministry on Sunday, the anniversary of the start of the ground campaign in Gaza, more than 30 soldiers have died in combat in southern Lebanon since Oct. 1, when the ground invasion there began, along with nearly 10 in Israel related to that conflict. In Gaza, about 15 soldiers died in the same period.

“It has been a year of war on multiple fronts,” said Lt. Gen. Herzi Halevi, the chief of staff of the Israeli military, adding in a statement addressing soldiers on Sunday that “no war comes without a cost.”

“Our continued existence is ensured by the acts of heroism of the fallen and the wounded in body or soul,” General Halevi said. “It is our duty to complete the mission for them.”

According to the Israeli authorities, 360 soldiers have died in the fighting in the Gaza Strip over more than a year of war.

In the same period, the fighting in Gaza has cost more than 43,000 Palestinian lives, according to the Palestinian Ministry of Health in Gaza, which does not distinguish between combatant and civilian deaths. The Israeli military said this summer that it had killed about 17,000 Hamas operatives in Gaza. Most of the population of 2.2 million Gazans has been displaced.

Israeli troops invaded southern Lebanon at the start of October to fight Hezbollah, an Iranian-backed militia that began firing rockets on northern Israel just after the war in Gaza began, expressing support for Hamas, which is also backed by Iran. The Israeli military described a limited invasion meant to dismantle Hezbollah’s infrastructure and ensure that more than 60,000 Israelis who fled their homes in the north could return and live in security.

An even larger number of residents of southern Lebanon had been displaced over the year of cross-border fire, and the Israeli ground invasion has displaced hundreds of thousands more, according to the International Organization for Migration, a United Nations arm. More than 2,600 people have been killed in Lebanon during the conflict, the vast majority in recent weeks, according to the Lebanese Health Ministry.

Hezbollah has the largest arsenal of any nonstate armed group in the world, and its fighters have been battle-hardened in wars with Israel, and in fighting in Syria. They are considered better armed and more capable than Hamas.

The military’s losses in Gaza in November of last year, the first full month of Israeli ground troops fighting in the enclave, roughly equaled October’s toll in the two conflicts, with about 55 soldiers killed in combat. In January, previously the deadliest month of this year for Israeli soldiers, more than 50 service members were killed in combat in Gaza.

Daniel Byman, a senior fellow with the Warfare, Irregular Threats, and Terrorism Program at the Center for Strategic and International Studies in Washington, assessed that on a scale of 100, Hezbollah would have been at a 90 before the war with Israel began, meaning extremely capable, while Hamas had been at about a 50. Fighting Hezbollah will be difficult, he said.

Prime Minister Benjamin Netanyahu’s coalition controls the Knesset, or parliament. The coalition is made up of his right-wing Likud party, the largest, which governs with six smaller parties, including two from the far right.

Here is a look at the UNRWA bill and some key legislative items on the agenda:

UNRWA

After the new session began, the Knesset enacted two laws that barred UNRWA’s operations in the country.

In doing so, Israel defied calls from the Biden administration, which has warned that the legislation could prompt an even greater humanitarian crisis in Gaza.

Most of the provisions in the laws will not take effect for another three months and their full legal ramifications were not immediately clear. But they could hobble UNRWA’s work in Gaza, where the relief agency has played a critical role in coordinating desperately needed humanitarian aid.

Israel has criticized UNRWA for decades, arguing that its work for Palestinian refugees and their descendants further perpetuated the conflict. The Israeli government has accused at least 19 of the agency’s employees of participating in the Hamas-led attack on Israel that triggered the war last October, nine of whom were later fired for possible involvement.

But the legislation passed on Monday night had the potential to push UNRWA’s operations into precarious and uncharted territory.

Conscription

Israel’s Supreme Court issued a ruling in June that there was no legal basis for the longstanding military exemption given to ultra-Orthodox religious students and, as a result, the military must begin drafting ultra-Orthodox Jewish men.

The exemption has polarized Israeli society, pitting secular Jews against the ultra-Orthodox, who say their religious study is as essential and protective as the military. Division over the issue has intensified during the wars in Gaza and Lebanon, with some arguing that the exemption unfairly places the burden of military service on Israelis who are not ultra-Orthodox. The ruling also exposed the fault lines in Mr. Netanyahu’s coalition, which depends on the support of two ultra-Orthodox parties that oppose ending the exemption.

At the same time, the matter is a source of tension between Mr. Netanyahu and defense minister Yoav Gallant, who wants a broader consensus over the issue. Mr. Gallant voted against a draft bill on enlistment in June.

Lawmakers are expected to introduce bills to translate the court’s ruling into legislation. The government has been seeking a compromise over the issue, according to Israeli media reports. The chairman of the Knesset’s foreign affairs committee, Yuli Edelstein, has said on social media that he is pursuing a deal that he hoped would be acceptable to all parties.

Israel’s state broadcaster, Kan, reported that Mr. Netanyahu called on Monday for accelerated talks between ultra-Orthodox parties and pushed Mr. Edelstein to find a compromise. The timing of any potential legislation is unclear.

Incitement to terrorism

The Knesset will consider a bill brought by right-wing lawmakers that could make it easier for the police to open an investigation into a person on suspicion of incitement to terrorism.

The bill says that “identifying with a terrorist organization is a criminal offense,” if “the act has a real possibility that this will lead to the performance of an act of terrorism.”

In practice, critics said the bill would lower the bar for investigations of individuals for social media posts and other forms of speech about security issues. The Knesset has already voted in favor of advancing the bill and it is being prepared for a second and third reading.

Civil rights groups have accused the police of the political persecution of Palestinian citizens of Israel since the attack by Hamas last Oct. 7, and Adalah, a legal center for the rights of the Arab minority in Israel, said last week that the bill would institutionalize that persecution.

Police records showed in May that 162 indictments for incitement to terrorism had been filed since the Hamas-led Oct. 7 attack last year. According to Adalah, nearly every case involved Arab citizens of Israel or Palestinian residents of East Jerusalem, who have mostly declined to apply for citizenship after Israel annexed the area.

The Israel Defense Forces, which invaded southern Lebanon on Oct. 1, said they had struck “Hezbollah weapons and anti-tank-missile storage facilities, terrorist infrastructure and observation posts” in the Tyre area. Civilians had been warned to leave before the strikes, the military said in a statement.

There were no immediate reports of casualties. Most of the city’s residents had fled before a previous round of strikes on the city last week. At that time, Lebanon’s culture ministry condemned the attacks and called on UNESCO to intervene to protect the city’s archaeological sites.

But few expect a conclusive result from either effort before the election next Tuesday, with Prime Minister Benjamin Netanyahu of Israel waiting to see who will succeed President Biden before committing to a diplomatic trajectory, according to four officials briefed on Israel’s internal thinking. The officials spoke on the condition of anonymity in order to discuss sensitive diplomacy.

A senior official from Hamas has also already rejected the premise of a 48-hour cease-fire in Gaza, an idea proposed by Egypt over the weekend, during which Hamas would release a handful of Israeli hostages in exchange for Palestinians imprisoned in Israel. Osama Hamdan, a Hamas leader, said on Sunday that the group would only agree to a permanent cessation of hostilities, dashing hopes that Israel’s recent killing of the group’s leader, Yahya Sinwar, would bring about a swift change in its negotiating position.

By contrast, Mr. Netanyahu has repeatedly said that he can only agree to a temporary arrangement that would allow Israeli forces to resume fighting. The prime minister’s coalition depends on several far-right lawmakers and ministers who have threatened to bring down the government if it allows Hamas to remain in power in Gaza.

While Mr. Netanyahu could still compromise he is likely waiting to see whether Vice President Kamala Harris or former President Donald J. Trump will lead the United States for the next four years, in order to assess how much leeway he will have from Israel’s main benefactor and ally, officials and analysts said.

“I don’t see any huge deal that is going to end the war in the next week,” said Nadav Shtrauchler, a political analyst and former strategist for Mr. Netanyahu.

“The perception is that Trump will do more for Netanyahu,” Mr. Shtrauchler added. “So I don’t see Netanyahu making major moves when in a week he will know more about where the U.S. is going.”

Mr. Trump favored Israel when previously in office, moving the U.S. Embassy to Jerusalem from Tel Aviv, legitimizing Israeli settlements in the occupied West Bank and recognizing Israeli sovereignty in the Golan Heights, a territory that Israel captured from Syria during the Arab-Israeli war of 1967.

If re-elected, some analysts say, Mr. Trump would be likelier than Kamala Harris to accept long-term Israeli control of parts of Gaza, as well as bigger Israeli military operations in Lebanon and Iran.

While Mr. Trump is unpredictable and can confound expectations, he would also likely “lean in favor of Israel leading more military strikes inside Tehran,” said Ellie Geranmayeh, a Middle East expert at the European Council on Foreign Relations, a Berlin-based research group. “This would further corner Iran, and embolden Bibi, making it much harder to calm the Gaza and Lebanon wars,” she added, using a nickname for Mr. Netanyahu.

If Ms. Harris is elected, the United States is unlikely to reduce its longstanding financial and military support for Israel, a policy that has strong bipartisan support in Washington. But she would probably continue Mr. Biden’s efforts to urge Israel to cease-fires in Gaza and Lebanon and keep the conflict with Iran from becoming a full-blown war, analysts said.

“Harris is likely to pursue continuity — pushing for de-escalation deals across the region aimed at cooling tensions and refocusing U.S. resources elsewhere,” Ms. Geranmayeh said.

Reporting was contributed by Natan Odenheimer, Adam Rasgon and Myra Noveck in Jerusalem, and Gabby Sobelman in Rehovot, Israel.

There were no major gun battles inside the hospital complex once troops entered, according to the Israeli military official, who briefed reporters on condition of anonymity, citing the sensitivity of the operation.

The Gaza health ministry said in a statement on Monday that Israeli forces had “detained or expelled all the medical staff” at the hospital, and that only one pediatrician remained there. The statement also called on international organizations to send medical teams to the hospital and urged people with surgical skills in Gaza to come to the hospital to save those who could be saved among the wounded and sick.

The Israeli military official added that Israeli troops had dismantled oxygen tanks at the hospital to ensure that they weren’t booby-trapped. “We haven’t damaged the medical infrastructure, but specific findings that we had there we had to dismantle, and that’s the reason we’ve seen damage,” he said.

Last Thursday, a U.N. World Health Organization team that visited the hospital to deliver supplies reported a chaotic scene, with injured people lying on the floors and medical staff overwhelmed. The next morning, the Gaza health ministry said that Israeli forces had stormed the complex and were “detaining hundreds of patients, medical staff and some displaced people,” and the W.H.O.’s director said it had lost contact with staff at the hospital.

Later on Friday, the health ministry said that the situation at the hospital was “alarmingly deteriorating” as Israeli troops searched it and fired shots, causing panic among the roughly 600 people inside. Two children in the intensive care unit died after generators stopped working during the Israeli military operation, the ministry said.

The Israeli military did not comment on the reports that patients had died. It said in a statement on Monday that the hospital had been provided with medical and other supplies, including fuel and blood, and that 88 patients, caregivers and staff members had been relocated to other hospitals in Gaza in recent weeks.

Israeli forces had previously besieged and raided Kamal Adwan Hospital last December and detained its director. This month, the Gaza health ministry said the hospital was one of three that the Israeli military had ordered to evacuate as its forces launched a new offensive targeting what it said was a Hamas resurgence in northern Gaza.

Aaron Boxerman contributed reporting from Jerusalem and Gabby Sobelman from Rehovot, Israel.

Now, as Israel unleashes attacks against its enemies — including Hezbollah in Lebanon, Hamas in Gaza and their backer, Iran — President Biden finds his influence severely limited. Rather than the grand peacemaking or wars of his predecessors, he is engaged mostly in diplomatic cleanup operations.

Some U.S. efforts have shown signs of influence: Israel heeded American warnings not to strike sensitive nuclear enrichment sites or oil production facilities in Iran, in retaliation for Iran’s bombardment of Israel with ballistic missiles early this month.

But more ambitious efforts, like American-led negotiations for a cease-fire with Hamas in Gaza, have failed to produce a breakthrough. And the United States has yet to propose, much less carry out, a comprehensive plan that would pull the Middle East back from a calamitous regionwide war.

Nor does it appear to have much influence on the Israeli leader, Prime Minister Benjamin Netanyahu, who has ramped up the conflict with Hezbollah and Iran, and continued the military campaign in Gaza, despite having killed the Hamas leader, Yahya Sinwar.

A junior partner takes charge

Mr. Netanyahu’s aim, experts said, is to use the impetus of the Oct. 7 Hamas attacks to vanquish Israel’s enemies across the board. Israel’s defenders cast it as a once-in-a-generation opportunity to reshape the region’s perilous landscape. Critics say Israel is escalating the conflict without any plan for what comes afterward.

“You have a disconnect where the junior partner in the alliance has the grander vision for the region, and the senior partner is left trying to respond to events,” said Vali R. Nasr, a State Department official in the Obama administration who is now a professor at the Johns Hopkins School of Advanced International Studies. “This is not a good place for the United States to be.”

Rivals like China and Russia are taking note of the United States’ inability to curb Israel or contain the conflict in the Middle East, Mr. Nasr said. That could deepen President Vladimir V. Putin’s resolve to crush Ukraine or embolden President Xi Jinping of China to move against Taiwan.

What’s more, a wider conflict in the region would almost inevitably draw in the United States. It has already deployed warships to the Mediterranean Sea to deter Hezbollah and Iran, deployed commandos to Israel to help hunt for hostages and Hamas leaders, and helped Israel shoot down Iranian missiles.

“Core to the assumption of the Israelis is that in a wider war, the United States will be doing the fighting,” Mr. Nasr said. “The United States is sleepwalking into another long-term conflict in the Middle East.”

U.S. election uncertainty

The Middle East conflict is taking place during a period of acute political uncertainty in the United States. Israel’s retaliatory strike against Iran came just 10 days before a presidential election that appears to be a dead heat between Vice President Kamala Harris and former President Donald J. Trump.

Ms. Harris has shown little daylight between her and President Biden on the Gaza war, despite acknowledging that the White House’s policy of steadfast support for Israel has caused her problems on the campaign trail.

Mr. Trump has had his own problems with Mr. Netanyahu, dating back to 2020, when the Israeli leader angered Mr. Trump by congratulating Mr. Biden on his election victory. But in recent comments, and in a phone call with Mr. Netanyahu, Mr. Trump gave strong backing for the Israeli campaigns against Hamas and Hezbollah.

“Biden is trying to hold him back,” Mr. Trump said to reporters last week, when asked about Mr. Netanyahu. “He’s trying to hold him back, and he probably should be doing the opposite, actually.”

The careful calibration of the Israeli strikes on Friday may have kept Israel’s options open ahead of the election. A more aggressive strike might have soured relations with a future Harris administration. If Mr. Trump wins, analysts said, Israel could take more aggressive action against Iran, such as targeting energy or nuclear facilities.

They also said that if Mr. Trump was elected, they would expect an effort to expand the Abraham Accords, under which several gulf countries normalized relations with Israel during the Trump administration. But without a halt to the war in Gaza, and some hint of a path to a two-state solution for Palestinians, Saudi Arabia would be unlikely to move in Israel’s direction.

Under a President Harris, these analysts said, the United States would be more likely to pursue an “integrated approach,” addressing the Israeli-Palestinian problem, as well as Israel’s relations with its Arab and Muslim neighbors. But Mr. Biden’s inability to make much progress is a bleak omen.

Michael B. Oren, a former Israeli ambassador to the United States, said there was much in common between Mr. Netanyahu’s vision and Mr. Biden’s, despite their disagreement over the need for a Palestinian state.

But Mr. Oren said that even in the wake of the Oct. 7 attacks, “the White House believes their vision can be achieved without a preponderance of military force, while Netanyahu knows it cannot.”

Conflict as a prelude to peace

Historically, diplomats said, the United States has been able to use upheaval in the Middle East to push for change. The 1973 Yom Kippur War planted the seeds for the Camp David accord between Israel and Egypt. The first Palestinian intifada set the stage for peace talks during the Clinton administration.

“For sure, there’s a moment of hope here,” said Daniel C. Kurtzer, a former American ambassador to Israel and Egypt. “If you’re Israel and you have seriously weakened three of your most important enemies, you might say to yourself, ‘This is an opportunity to move the notch closer to regional stability and peace.’”

Yet what separates the current conflict from previous ones, Mr. Kurtzer said, is both the brutal nature of the Hamas attack on Israel, which left its population traumatized in a way that previous wars did not, and the uncertain leadership in several key countries, not just the United States.

Iran, for example, has reacted fitfully to the confrontation with Israel. That reflects its own leadership succession questions, economic problems and domestic unrest, as well as the damage Israel has inflicted on its proxies.

As for Israel, Mr. Netanyahu still faces the prospect of prosecution over corruption cases, and he governs in a coalition with far-right ministers, some of whom view the Gaza conflict as a pretext to drive out the Palestinian population.

“There’s a vision there, but it’s not going to work,” said Mr. Kurtzer, who teaches at Princeton. “It will only perpetuate the conflict.”