In the turbulent landscape of the Middle East, Iran’s aging supreme leader, Ayatollah Ali Khamenei, could always rely on the close alliance, unwavering loyalty and deep friendship of Hassan Nasrallah, the leader of the Lebanese militia Hezbollah.

When Israel killed Mr. Nasrallah in a massive airstrike on Friday, it abruptly wiped out a singular force in Mr. Khamenei’s hierarchy of close associates.

Iran had for 40 years nurtured Hezbollah as the main arm of its proxy network of militias, as a forward defense against Israel. But in the past two weeks, Hezbollah’s capacity began to crumble under wave after wave of Israeli attacks on its leadership, arsenal and communications.

Now, fissures have opened within the Iranian government over how to respond to Mr. Nasrallah’s killing, with conservatives arguing for a forceful response and the moderates, led by Iran’s new president, Masoud Pezeshkian, calling for restraint.

All of this has left Iran, and its supreme leader, in a vulnerable position.

Four Iranian officials who knew Mr. Nasrallah personally and had been briefed on events said that Mr. Khamenei had been deeply shaken by his friend’s death and was in mourning, but had assumed a calm and pragmatic posture. The officials, including two members of the Islamic Revolutionary Guard Corps, requested anonymity as they were not authorized to speak publicly.

Mr. Khamenei struck much the same tone in public. Instead of lashing out at Israel, he issued two restrained statements, praising Mr. Nasrallah as a leading figure in the Muslim world and the so-called axis of resistance, and saying that Iran would stand by Hezbollah.

Significantly, Mr. Khamenei signaled that it would be Hezbollah, not Iran, that would be leading any response to Israel, and that Iran would play a supporting role. “All of the forces in the resistance stand by Hezbollah,” Mr. Khamenei said. “It will be Hezbollah, at the helm of the resistance forces, that will determine the fate of the region.”

It was a striking sign, some analysts said, that Mr. Khamenei may have no way to effectively respond at the moment to Israel’s onslaught on his proxies. Faced with a choice between all-out war with Israel or lying low in the interest of self-preservation, he appears to be choosing the latter.

“They are completely checkmated by Israel at this moment,” said Sanam Vakil, the director for Middle East at Chatham House. “Khamenei’s statement is indicative of the gravity of the moment and the caution; he is not publicly committing to anything that he can’t deliver.”

After Mr. Khamenei’s statements, a flurry of reactions from senior Iranian officials and military commanders had the same cautious tone, outsourcing revenge to other militia groups in the region. Gen. Hossein Salami, the commander in chief of the Revolutionary Guards, said that it would be “Hezbollah, Hamas and other Palestinian militants” that would deliver blows to Israel.

In Tehran, the news of Mr. Nasrallah’s death cast a pall of shock and anxiety over senior officials who wondered in private phone calls and during emergency meetings if Israel would strike Iran next, and if Mr. Khamenei would be its next target, the four Iranian officials said in telephone interviews.

“This was an incredibly heavy blow, and realistically speaking, we have no clear path for recovering from this loss,” Mohammad Ali Abtahi, a former vice president of Iran, said in an interview from Tehran on Saturday. “We will not go to war, that’s off the table. But Iran will also not reverse course in supporting the militant groups in the region, nor in defusing tensions with the West. All of these things can be pursued at the same time.”

Mr. Abtahi said the collective feeling among Iranian officials was one of “shock, anger, sadness and a lot of anxiety.”

This was far different from the sentiment after Hamas’s Oct. 7 attacks on Israel, when Iran and its other proxies celebrated the surprise incursion. At that time, Hezbollah almost immediately attacked Israel’s north with rockets and continued exchanging fire. Iran gradually activated its network of militant groups known collectively as the “axis of resistance” to open fronts against Israel and create chaos in the region to pressure both the United States and Israel into a cease-fire with Hamas.

For Iran, the gamble was to keep the pressure percolating without setting off an all-out regional war.

In many ways, the yearlong confrontation between Iran and its proxies and Israel came to a violent head when Mr. Nasrallah was killed. Iran’s effort to weaken Israel through its proxies has appeared to backfire, leading to a catastrophic blow against its most strategic ally.

When the news broke that Israel had most likely killed Mr. Nasrallah, Mr. Khamenei convened an emergency meeting of the Supreme National Security Council at his home, the Iranian officials said. During the meeting, people were divided on how to respond.

Conservative members, including Saeed Jalili, an influential former presidential candidate, argued that Iran needed to quickly establish deterrence with a strike on Israel, before Israel’s prime minister, Benjamin Netanyahu, brought the war to Tehran, according to officials familiar with the meeting.

Iran’s new president, Mr. Pezeshkian, who spent last week telling world leaders at the United Nations General Assembly that his government wanted to defuse tensions and get along with the West, argued against such a response, saying that Iran should not fall into a trap being set by Mr. Netanyahu for a wider war, the Iranian officials said.

Other moderate voices on the council argued that Mr. Netanyahu had blown through all red lines, and that if it launched attacks on Israel, Iran could face dire attacks on its own critical infrastructure, something the country could not afford, those officials said, particularly given the dire state of the economy.

But state television, run by Mr. Jalili’s affiliates, called for Iran to strike Israel, in open defiance of Mr. Khamenei’s caution. “There is no difference between Tehran and Baghdad and Beirut, the regime will come after each of these targets,” the anchor of state television said. “Netanyahu only understands one language, and that’s ballistic missiles and drones.”

Domestically, Iran has faced a cascade of challenges, from public discontent against government corruption and mismanagement of the economy and widespread hardship to Israel’s infiltration into Iran’s military and political ranks.

In New York, Mr. Pezeshkian told reporters that Iran was ready to “lay down its arms if Israel laid down its arms,” and called for an international force to intervene in establishing peace in the Middle East.

Mr. Pezeshkian has had to contend with two major crises during his two months in office: the Israeli assassination of the Hamas political leader, Ismail Haniyeh, in Tehran on the night of his inauguration and Mr. Nasrallah’s killing on the eve of his birthday.

Those crises made him an easy target among conservatives in Iran who criticized his conciliatory message in New York, saying it showed weakness and emboldened Israel to kill Mr. Nasrallah. The conservatives argued Iran should deploy fighters to Lebanon, as it did for the Syrian government in its civil war, to help Hezbollah in the event of an all-out war with Israel.

“Israel has attacked the nucleus cell of the resistance and thus we cannot be indifferent,” said a conservative cleric, Ayatollah Mohammad Hassan Akhtari, the head of Iran’s Committee to Support Palestinians and the former head of international relations in Mr. Khamenei’s office.

Two members of the Revolutionary Guards — including a strategist who had been in planning meetings for the past two days on how Iran should respond — said in interviews that Iran’s immediate priority was to help Hezbollah get back on its feet, name a successor to Mr. Nasrallah, line up a new command structure and rebuild a safe communications network. Then, Hezbollah could plan its retaliation against Israel, they said.

Iran was planning to send a senior Quds Forces commander to Beirut by way of Syria to help guide Hezbollah’s recovery, the two Revolutionary Guards members said.

Mr. Khamenei announced five days of mourning in Iran, but across the country, the reaction to Mr. Nasrallah’s death was mixed. Supporters of the government staged public mourning ceremonies in Tehran’s Palestine Square. They waved the yellow flag of Hezbollah and chanted, “revenge, revenge,” and “death to Israel.”

But among dissidents, victims of the government’s brutal crackdowns and many ordinary Iranians, Mr. Nasrallah was viewed as an arm of the regime’s oppression. They rejoiced at his death, dancing in the streets and passing boxes of sweets at traffic stops in several cities, according to witnesses. Cars that passed by honked their horns in support.

Quebec is working hard to fortify its official language — much to the displeasure of some who don’t speak it.

Battling what many describe as the incursion of English has become a resounding political message in the province, North America’s largest French enclave. And Quebec’s government is finding more ways to lift the supremacy of French, the province’s lingua franca.

Provincial laws mandate that English text on storefront signs be half the size of French words and that employers reveal what percentage of their staff cannot work in French. New immigrants are given a six-month grace period before French becomes the only language in which they receive government services, such as taking a driver’s test.

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