Regional War: An Explainer

Answers to common questions about the broadening war in the Middle East.

Alex Kane and Jonathan Shamir
January 17, 2024

The aftermath of a January 9th Israeli airstrike on the car carrying elite Hezbollah commander Wissam Tawi, near the Israel–Lebanon border.

Hussein Malla / AP Photo

(This article also appeared in the Jewish Currents email newsletter; subscribe here!)

On January 13th, the United States and British air forces bombed 16 areas in Yemen, striking over 60 military sites controlled by the Houthi movement—an Islamist faction that has been targeting ships in the Red Sea in response to Israel’s war on Gaza. The bombings in Yemen marked the biggest US military operation in the Middle East since Hamas’s attack and Israel’s ongoing invasion of Gaza.

In the weeks since October 7th, Israel’s war has quickly spread to additional fronts. The Lebanese group Hezbollah and Israel have been attacking each other along the Israel–Lebanon border (also called the “blue line”), and the smaller strikes have now escalated to include high-profile Israeli assassinations of Hamas and Hezbollah military leaders. Today, Israel’s military chief Herzi Halevi said that the Israeli army is ramping up its preparations for an increasingly likely full-scale war with Hezbollah. At the same time, the US has exchanged strikes with Iraqi and Syrian forces, and now the US has bombed Yemen.

Experts say this violence already amounts to a nascent regional war—and some argue that the US’s consistent backing of Israel’s assault could spur an even deeper conflict. “It hasn’t elevated all the way to all-out total war,” said Thanassis Cambanis, director of the Century Foundation’s international research and policy center. However, he added, such a war is still possible. In particular, because the fighting so far has pitted a US-aligned axis against an Iran-aligned one, an escalatory spiral could lead, in the most extreme scenario, to a US-Iran war. Whether or not this happens, according to Cambanis, depends on if “the US uses its leverage to draw back—containing and then stopping the regional war—or if it just escalates from here.”

Jewish Currents put together this explainer to break down why Israel’s war on Gaza sparked fighting in the Middle East, including details about Hezbollah, Israel’s escalations in Lebanon, the Houthi movement, Iran’s strategy, and more.

What is Hezbollah?

Hezbollah is a Shiite Islamist political movement based in Lebanon. The group was originally founded to resist Israel’s occupation of southern Lebanon during the 1980s, and is largely credited with carrying out a series of attacks that led to Israel’s eventual withdrawal from the country in 2000.

In the decades since, Hezbollah—which is supported by Iran—has become a powerful political faction in Lebanon, establishing its own media outlets and growing its extensive social welfare network for the Shiite poor. Since 1992, Hezbollah has also run for political office, and has served in every government since 2005. “Hezbollah is a true mass movement that is embedded in Lebanese society,” Joseph Daher, an academic and the author of a book on the group, told Jewish Currents. Throughout that time, Hezbollah has also strengthened its military wing, and the group’s arsenal of 100,000 rockets, 20,000 active fighters, and tens of thousands of reservists has made it “the world’s most heavily armed non-state actor,” according to the Center for International Studies, with its power outstripping the US-backed Lebanese army itself. Through intervening in Syria’s civil war on behalf of Syrian President Bashar al-Assad, the group has also gained significant experience in battle.

Hezbollah views its arms and fighters as key to defending Lebanon’s sovereignty, especially from Israeli threats. According to Cambanis, “Israel is constantly violating Lebanon’s sovereignty” with frequent incursions into Lebanon’s airspace and bombings of Hezbollah assets. Cambanis says Israel views these actions as a way to deter Hezbollah; however, rather than being dissuaded, Hezbollah has repeatedly responded to these incursions by allowing Palestinian factions operating in Lebanon to fire at Israel, or even firing back itself. “Hezbollah’s armed maneuvers are trying to deter further and deeper violations of Lebanese sovereignty by Israel,” said Cambanis.

How has fighting between Israel and Hezbollah played out since October 7th?

The constant hostilities around the blue line have intensified since October 7th. On October 8th, Hezbollah—a staunch ally of Hamas—fired rockets and artillery shells at Israeli military positions in Shebaa Farms, an area Lebanon claims but that Israel has controlled since the 1967 war. Hezbollah says it launched the attack to show solidarity with Palestinians and to force Israel to divert military assets to the north as a way to reduce military pressure on Hamas. In response, Israel fired back, and ever since, Israel and Hezbollah have fired at each other hundreds of times. In Lebanon, Israeli airstrikes and tank fire have killed over 130 Hezbollah fighters and two dozen civilians, while Hezbollah rockets have killed nine soldiers and six civilians in Israel. Approximately 60,000 people in the communities on each side of the blue line have been evacuated from their homes.

Despite Hezbollah’s close ties to Hamas, however, analysts say the group does not want full-blown war with Israel. Hezbollah’s popularity has already been waning due to its role in interethnic conflict, its corruption, and its crushing of dissent in Lebanon; a deadly war with the much-stronger Israel could further endanger its position, and might end up empowering its domestic rivals. “While there is large-scale support for Palestinians across the political spectrum, most people in Lebanon do not want war,” Daher said. This opposition is shared by Hezbollah’s backer, Iran, which provides the group with arms and funding, and which too wants to avoid a war that could endanger Hezbollah’s position. “Iran wants to retain its strength in Lebanon as a long-run deterrence tactic against Israel,” said Trita Parsi, the executive vice-president of the Quincy Institute, an anti-interventionist think tank. These political constraints explain Hezbollah fighters’ relative restraint against Israel. “They could rain rockets over Tel Aviv, and target important urban sites and infrastructure, but they are not doing that so far,” said Daher.

What is Israel’s approach towards Hezbollah now?

Prior to Hamas’s October 7th attack, Israel saw Hamas and Hezbollah “as largely a tactical problem rather than a strategic threat,” said David Schenker, director of the Washington Institute’s program on Arab politics and a former assistant secretary of state for Near Eastern affairs during the Trump administration—such that Israel was inclined to manage them with periodic smaller campaigns rather than seeing their existence as a fundamental problem. After October 7th, however, the Israeli view completely changed. “They are acting [against Hezbollah] robustly and want to change the status quo so that Hezbollah’s elite special forces can no longer be on the border with Israel. Israel is no longer willing to tolerate this dynamic,” Schenker said.

Since fighting between Hezbollah and Israel began, Israeli officials have made bold threats. “What we are doing in Gaza we can do in Beirut,” Israeli Defense Minister Yoav Gallant told Israeli troops on November 11th. Despite this rhetoric, however, Israeli leaders have been split on the way forward, said Heiko Wimmen, who oversees the International Crisis Group’s Iraq/Syria/Lebanon project. Given low Israeli casualties near the border, “there are at least some people in the Israeli system who think that actually, the situation is not that bad,” he said. As a result, Israel was initially restrained in its tit-for-tat strikes with Hezbollah, staying within three to six miles on either side of the border.

But on January 2nd, an Israeli drone strike deep inside Lebanon—in southern Beirut—killed Saleh al-Arouri, the deputy chief of Hamas’s political bureau and one of the founders of its military wing. This was an escalatory move by Israel “because of the location where it occurred: In Beirut, in Hezbollah’s center of gravity,” according to Wimmen. It was also an escalation in terms of who was targeted: Unlike previous Israeli strikes, which only hit militants involved in operations against Israel, Arouri was “not an actual combatant,” Wimmen said. At the same time, unlike many of its widely destructive operations in Gaza, Israel’s killing of Arouri was a “precise surgical strike” that killed the high-ranking Hamas member and six other Hamas officials but no Lebanese civilians. “Israel wanted to conduct the strike in a way that would not force Hezbollah’s hand,” said Wimmen. Other such assassinations have followed, and while none have so far sparked full-on war, the possibility remains open. Especially if “Israel brings down a whole building in Beirut, killing many Shia Lebanese civilians,” Wimmen said, “Hezbollah would be under a different kind of pressure to respond.”

What is the Houthi movement?

The Houthi insurgency is a Zaydi Shiite Islamist political movement established in 1992 to challenge Yemen’s longtime, and increasingly corrupt, leader Ali Abdullah Saleh. Following massive street protests, Saleh resigned his post in 2011. After the resignation, a national unity dialogue was held in Yemen’s capital Sana’a to try to resolve a host of Yemeni political conflicts. However, those talks eventually broke down, prompting the Houthis to advance on Sana’a with the goal of taking power. This sparked Saudi Arabia’s deadly US-backed air, ground, and naval invasion of Yemen, which lasted for seven years and killed an estimated 9,000 civilians, as well as significant numbers of Houthi forces, in repeated airstrikes. Despite the overwhelming force used by Saudi Arabia, however, the Houthis gained control over roughly a third of Yemen’s land—and two-thirds of its population—over the course of the war.

In April 2022, Saudi Arabia and the Houthis negotiated a truce that has nearly eliminated the fighting in Yemen. The truce halted offensive military operations, allowed fuel ships to enter Yemeni ports, and restarted commercial flights from Sana’a airport. However, it did not offer a comprehensive political settlement, leaving open the threat of renewed hostilities.

How have the Houthis become involved in the war?

After Israel began bombing Gaza on October 7th, the Houthi movement—which has long held what Yemen expert Helen Lackner called a “fundamentalist foreign policy position against the US and Israel”—announced that it was ready to intervene in solidarity with Palestinians. “There are red lines in the situation related to Gaza, and we are coordinating with our brothers in the jihad axis and are ready to intervene with all we can,” the Houthis’ leader said. As part of this effort, the movement has carried out 27 attacks in the Red Sea between November 19th and January 11th, most of them on commercial ships linked to Israel (although some of the attacks have targeted ships without a clear connection to Israel). The movement has also tried to fire on American warships and on Israel itself.

In the attacks on commercial ships, the Houthis have mostly fired missiles at them, though on November 20th, the group’s fighters seized a cargo ship and detained the crew members onboard. These attacks have discouraged shipping companies from traversing the Red Sea, the fastest route from Asia to Europe; many are instead sailing around the Horn of Africa, which adds $1 million to the typical cost of a roundtrip. On January 11th, the White House cited this trade disruption as a key motivating factor for the US’s bombings in Yemen, noting that “more than 2,000 ships have been forced to divert thousands of miles to avoid the Red Sea—which can cause weeks of delays in product shipping times.”

The Houthi movement’s attacks in the Red Sea, as well as the retaliation the attacks have generated, have revitalized the group’s power within Yemen. Prior to October 7th, the Houthis were facing discontent due to their authoritarian rule, their failure to pay salaries, and their control of aid in the face of spiraling poverty. Their confrontation with Israel, however, has seen “their popularity suddenly skyrocket, including in areas in Yemen where they don’t rule and in stark contrast to other Arab [states] who are at best being silent, or at worse, helping the enemy,” Yemen expert Helen Lackner told Jewish Currents. After incurring significant losses in their conflict with Saudi Arabia and the United Arab Emirates, the Houthis’ firm opposition to Israel has also helped them to recruit more young men to their military who believe they will have the opportunity to fight in Palestine, according to Lackner.

In this context, experts say it is unlikely the spate of Western bombings will end the Houthi attacks in the Red Sea—and such attacks could even contribute to the group’s bolstered popularity. “They’re willing to live with some level of retaliation because they can then position themselves as having been targeted by this Western alliance that is serving the interests of Israel,” said Mohamad Bazzi, director of New York University’s Kevorkian Center for Near Eastern Studies. Other experts have also warned that the US strikes risk provoking further escalations: For instance, the Houthis could decide to attack Saudi Arabia in a bid to up the pressure on American allies.

What is happening in Iraq and Syria?

In both Iraq and Syria, paramilitary forces—supported by Iran—have long launched salvos at US troops stationed in the area in attempts to dislodge their foreign presence. But since Israel’s assault on Gaza, these attacks have increased. Since October, Iraqi paramilitaries have fired dozens of rockets, drones, mortars, and missiles at US forces stationed in the country. In response, US forces have bombed ten Iraqi sites, killing an estimated 18 militants. On January 4th, the US killed one paramilitary commander in Baghdad in an airstrike, raising tensions with the Iraqi government, which called the assassination an “assault” on Iraq. In Syria, too, militants have fired dozens of rockets on US troops; the ensuing US airstrikes have killed an estimated 25 fighters.

What is Iran’s role in the regional escalation?

While the groups responding to Israel’s bombing of Gaza—Hamas, Hezbollah, the Houthis, and the Iraqi and Syrian paramilitaries—are spread out across the region, they are all supported by Iran, which has armed and financed them as part of an overall strategy to contest US and Israeli hegemony in the Middle East. This Iran-supported network is often called the “axis of resistance,” and the alliance’s close collaboration reflects an approach developed by Qassem Soleimani, who was a key Iranian military leader until he was assassinated by the US in January 2020. “A big part of his strategy in the region was for the groups to get to know each other, and to share training and expertise—and that continued after the assassination in Baghdad,” said Bazzi.

Experts emphasize that Iran does not have full control over the groups it funds and arms, which often pursue their own agendas. For example, the relationship between the Houthis and Iran, according to Lackner, “is a bit like Netanyahu’s relationship to Biden. If they agree, and they want to do the same thing, then they do it. But they are not afraid to diverge either,” said Lackner. For instance, the Houthis ignored Iran’s orders to halt their advance on Sana’a in 2014, which sparked the years-long civil war and the conflict with Saudi Arabia. In the current conflagration, Bazzi said, Iran is unlikely to be directing the various forces to pursue “specific attacks,” but Iranian military leadership is “probably involved in larger-scale conversations about the division of responsibilities of different parts of the axis of resistance.”

According to Bazzi, at this moment Iran is carefully calculating how to maintain regional credibility by showing support for Hamas, while not going far enough to provoke a war with powerful foes like the US and Israel. “The primary Iranian calculation is about regime survival, and they don’t want to do anything that seriously jeopardizes their survival,” said Bazzi. Parsi said that so far, Iran has benefited from avoiding risky moves—in contrast to Israel, which has diminished its own “global standing” with its operations in Gaza. “Israel’s pariah status globally—at least outside of the West—is something that the Iranians are drawing benefits from. But that only works to the point that this doesn’t escalate into a larger conflict,” he said.

How is the US responding to the regional conflict?

Since October 7th, the US has repeatedly said that it wants to prevent more fighting in the region. Early on, the US dispatched warships and fighter jets to the Mediterranean to deter Hezbollah from entering the fray. Biden administration officials have also ramped up diplomatic efforts to halt a regional conflagration: The president sent envoy Amos Hochstein to Lebanon to try to negotiate a solution to the fighting around the blue line, and reportedly warned Israel against escalation with Hezbollah in private conversations. In October, when Israel had made plans to pre-emptively strike Lebanon, President Biden called Netanyahu to tell him to “stand down” on the attack plans, and ultimately, Israel did not launch a wide scale attack, according to a December Wall Street Journal report. “The priority for the Biden administration is to limit or prevent the broadening of the conflict,” said Schenker.

At the same time, the US has carried out repeated bombings in Iraq, Syria, and now Yemen, even as officials continue to talk about de-escalation. “We’re not looking for conflict with Iran. We’re not looking to escalate and there’s no reason for it to escalate beyond what happened over the last few days,” National Security Council spokesman John Kirby said last Friday, after the first US bombings of Yemen. But yesterday, the US military again bombed Houthi targets for the third time in a week, and then designated the Houthis as a terror organization, blocking the group’s access to the global financial system. By targeting Yemen, experts say the US is significantly expanding the regional war—“escalating regional tensions and adding fuel to a conflict,” as Bazzi wrote in a recent column published in The Guardian. “The conflagration could spiral out of control, perhaps more by accident than design,” he noted.

Many Middle East analysts say the Biden administration’s attempt to avert regional war is failing for one main reason: its refusal to couple a plea for de-escalation with advocacy for a ceasefire in Gaza. “Seeing the wider regional conflict as something that can be managed separately from Gaza is the source of the dissonance [in the administration’s strategy],” Bazzi told Jewish Currents. “You can’t prevent the wider regional war effectively without addressing the core immediate issue, which is the Israeli assault on Gaza. It’s just wishful thinking in the Biden administration that somehow it can separate the two.”

Alex Kane is a senior reporter for Jewish Currents.

Jonathan Shamir is a Jewish Currents fellow and the former deputy editor of Haaretz.