JERUSALEM — At 3:30 p.m. on Sept. 17, someone pushed a “red button,” and a low-simmering conflict blasted open into a full-scale war.

For months, Israel and the Lebanese militant group Hezbollah had been locked in a cross-border slugfest, exchanging daily attacks that forced civilians in both countries from their homes but that never produced a military knockout or allowed for a diplomatic breakthrough.

But the moment that day when thousands of modified pagers detonated in the hands and pockets of Hezbollah members, Israel grabbed the initiative in the 11-month standoff, and it hasn’t let it go.

In the weeks since that audacious act of sabotage — the kind of hidden, long-embedded attack known as a “red button” operation - Israel has kept Hezbollah reeling, striking ever deeper into Lebanese territory to destroy the Iranian-backed group’s arsenal of missiles and killing its longtime charismatic leader, Hasan Nasrallah, and other senior commanders.

Last week, Israel escalated again, sending ground troops into southern Lebanon in its effort to push Hezbollah away from the border. Analysts credit Israel with a notable run of military wins, one that has boosted the mood of despondent Israelis and lifted the political fortunes of Prime Minister Benjamin Netanyahu, at least for now.

But experts in Israel and Washington are also asking: Now what? They say it is unclear how Israel’s surge of success against Hezbollah will bring meaningful changes — much less an end — to its fights against Iranian-backed forces in Lebanon, the Gaza Strip, the West Bank, Yemen and, now, perhaps with Iran itself.

Hezbollah may be in disarray, but the Shiite militant group, like Hamas, is an ideological movement unlikely to be entirely vanquished, they say. Even in a weakened state, Hezbollah units continue to fire missiles into Israel, sparking alert sirens in communities well south of the border zone.

Israel’s immediate stated goal is to allow the return of nearly 70,000 displaced Israelis to their homes in the north. The government has lambasted international peacekeepers for not helping keep Hezbollah away from the border, as stipulated in the 2006 U.N. Security Council resolution that governs the cease-fire from that war. The militant forces crowding the frontier not only fire into Israel, but they also pose the threat of a Hamas-style invasion into Israeli towns, Israel says.

But it will take far more pressure by the Israel Defense Forces to fully push Hezbollah beyond the eight or 10 miles that would keep its Russian Kornet antitank missiles — which have accounted for many of the estimated 10,000 projectiles it has fired at Israel this year — beyond the range of Israeli neighborhoods.

“How do any of these military successes translate into what they want, which is the return of Israelis to northern Israel,” said Aaron David Miller, senior fellow at the Carnegie Endowment for International Peace. “I can’t see a direct line to accomplishing that objective.”

An official familiar with thinking inside the Israeli government said planners recognized the limits to the recent military achievements.

“There is an Israeli strategy on how to hit Hezbollah,” said the official, who spoke on the condition of anonymity because they were not authorized to speak publicly. “But there is not necessarily a strategy of what comes next, how to get out of it.”

Israel, which suffered the worst military and intelligence failure in its history last October, has started to recover some of its military prowess. In Gaza and in Lebanon, its enemies are badly degraded if not destroyed. And the barrage of nearly 200 ballistic missiles Iran fired at Israel on Tuesday failed to cause widespread damage, although the IDF confirmed direct hits on two air bases.

“Hamas no longer exists as a military structure, Hezbollah is hollowed out,” and Iran’s strike resulted in only two injuries and the death a Palestinian man in the West Bank city of Jericho, Miller said. “There’s no question the balance has shifted.”

But it hasn’t shifted toward any decisive resolution, he said. Another, possibly larger exchange between Israel and Iran is expected. More than 100 Israeli hostages remain captive in Gaza, whether dead or alive. Cease-fire talks with Hamas have stalled, and Hezbollah has pledged to keep fighting as long as Israel is in Gaza.

“These wars are going to continue,” Miller said.

In Lebanon, the toll of Israel’s latest push has been devastating: More than 2,000 people have been killed and 1.2 million forced to flee, creating a spiraling humanitarian crisis.

Israel carried out its most intense barrage of airstrikes on Beirut’s southern suburbs on Saturday night, causing new waves of displacement across the capital, where the United Nations said thousands of people were sleeping in the streets. And Israeli strikes widened again over the weekend, hitting the north and east of the country.

Filippo Grandi, chief of the U.N. refugee agency, accused Israel on Sunday of carrying out numerous “egregious” violations of international humanitarian law since it escalated its attacks on Lebanon.

“We need respect for civilian infrastructure and the civilian population,” Grandi told reporters in Beirut, pointing in particular to attacks on hospitals, clinics and ambulances, which have killed at least 77 health workers, according to the Lebanese Health Ministry.

The IDF did not immediately respond to a request for comment.

Nine Israeli soldiers have been killed in the ground fighting, raising fears that a longer, deeper engagement in Lebanon could risk a repeat of previous incursions, including in 2006, when Israeli troops were immediately bogged down in firefights just north of the border.

Still, in Israel, the public has welcomed the progress against a feared enemy but remains nervous about the ever-expanding war. Public faith in the IDF, which had fallen, is back in typical ranges, with about three-quarters of Israelis rating its combat capability as good or excellent, according to a poll by the Israel Democracy Institute.

Netanyahu, too, has stabilized his plummeting public support and seen a rebound in the polls. The prime minister, in office for most of the last few years, was widely blamed for the failures leading up to the Oct. 7 attacks, including his strategy of allowing Hamas to gain strength as a rival to the Palestinian Authority in the West Bank. In recent months, a majority of Israelis have been angered at Netanyahu’s failure to reach a cease-fire deal that would bring hostages home from Gaza.

But since growing more aggressive against Hezbollah and Iran, Netanyahu’s support has ticked up.

“The regional dimension is much more unifying” than the stalemate in Gaza, Tel Aviv-based pollster Dahlia Scheindlin said. “Even people on the left see Hezbollah as a serious threat.”

Netanyahu’s Likud party now polls as the one likely to win the most seats in a theoretical election, although his coalition of right-wing, religious and nationalist parties would still fall far short of a parliamentary majority. Some potential coalitions of opposition parties would be closer to prevailing, Scheindlin said.

Israel says it is still mulling its response to the most recent Iranian attacks. The official familiar with Israeli government deliberations said there was a split on the course forward.

“There are those in the government who see an opportunity to hit Iran hard, to break the link between Iran and the proxy groups,” the official said. “The more moderate people think they need to work with the United States but worry that Biden doesn’t have a lot of power now.”

The Biden administration has counseled Israel to tally what it has achieved in significantly degrading Hezbollah and to take a deep breath before launching any retaliation, according to senior administration officials who spoke on the condition of anonymity to discuss sensitive communications.

Asked Friday to clarify his earlier remarks indicating that Israel might strike Iranian oil fields, President Joe Biden backtracked, telling reporters that “the Israelis have not concluded what they’re going to do in terms of a strike. That’s under discussion. If I was in their shoes, I’d be thinking about other alternatives than striking oil fields.”

Despite Israel’s bellicose rhetoric, officials said they believe it will consider a more calibrated response that will not invite another round of Iranian retaliation. Israel followed just such a restrained course after Iran’s barrage in April, mounting a limited return strike that caused minimal damage.

Although he has not spoken with Netanyahu in recent days, Biden said administration officials were in contact with Israel “constantly” and that the government there was “not going to make a decision immediately.”

But there have been few indications in the past that the Israelis are taking advice from the Americans. Since Oct. 7 and continuing throughout the war in Gaza, and now with Israel’s attacks on Hezbollah in Lebanon, Biden and his senior national security team have raised repeated concerns with Israel about its tactics and what they see as the absence of a larger strategy for long-term peace.

Any advice he is giving Israel now, Biden said Friday, “is between me and them.”

Israel, Biden said, has “every right to respond to the vicious attacks on them.” But at the same time, as the administration is worried about the expanding war in the Middle East, he raised another oft-stated concern. “The fact is that they have to be very much more careful about dealing with civilian casualties,” Biden said.

The fight with Hezbollah and Iran is still filled with uncertainties. The military has said it intends for its ground operations to be “limited,” but some Israeli politicians have called for an even more aggressive push to root the militant group from throughout Lebanon. Others have said the country has no intention of occupying the south once Hezbollah is no longer a force along the border.

Government and military leaders are wary of becoming mired in Lebanon, said the official familiar with Israeli government thinking:

“There is no will to have troops remain in Lebanon. In the past, that has cost a lot of soldiers’ lives and money. We call it ‘being stuck in the Lebanese mud.’”

Once southern Lebanon is largely cleared of Hezbollah fighters, weapons and tunnels, the IDF can monitor the border area and respond from Israeli territory, said Orna Mizrahi, a former deputy national security adviser and senior researcher at the Institute for National Security Studies.

“We understand that it’s going to be a very long, devastating war both for Israel and Lebanon,” Mizrahi said. “This is why I think that the government decided that the goal will be more limited, just to create the security reality to bring the people back home and not really to remove Hezbollah and all its capabilities.”

But on Sunday Israel issued new evacuation orders for additional towns and villages in the south of Lebanon — bringing the total number of border communities impacted by the orders to 98, according to a Washington Post tally, and signaling a possible expansion of the military’s war aims.

The absence of strategic clarity, in Lebanon and Gaza alike, reflects Israel’s lack of a broader plan for ending its longest stretch of war fighting since 1948, said Michael Milshtein, a former adviser to the military on Palestinian affairs.

The recent success of putting Hezbollah on its heels, while welcome, is no substitute for a long-term vision for the day after the guns finally fall silent, he said. If they ever do.

“Our basic problem, and it was very, very prominent during the last year in Gaza, is that if you do not have a clear strategy, it means you will be channeled to wars of attrition,” Milshtein said. “I’m very afraid that Israel, because of a gap in strategy, will find itself in ongoing wars in the north and in the south.”

Parker reported from Jerusalem, DeYoung from Washington and Cheeseman from Beirut. Ilan Ben Zion in Jerusalem contributed to this report.

previous coverage

• Mossad’s pager operation: Inside Israel’s penetration of Hezbollah