A war between Israel and Hezbollah would be devastating for both sides

The risk of war breaking out between Israel and Hezbollah – a far larger and more heavily armed force than Hamas – is so great that US President Joe Biden sent one of his top advisers, Amos Hochstein, to Israel and Lebanon last week to push for a solution.

US Defense Secretary Lloyd Austin told reporters on Tuesday that “diplomacy is by far the best way to prevent further escalation,” stressing: “We urgently seek a diplomatic settlement that will restore lasting calm to Israel’s northern border and allow civilians on both sides of the Israeli-Lebanese border to safely return to their homes.”

In the nearly nine months since Israel began its war against the Palestinian terror group Hamas in Gaza on October 7, Hezbollah has fired thousands of rockets at Israel. The rockets fired from Lebanon have killed 18 Israeli soldiers and 10 civilians, according to Israel, while Israeli shelling in Lebanon has killed around 300 Hezbollah fighters and around 80 civilians, according to a Reuters count.

At least 150,000 residents in southern Lebanon and northern Israel have been forced to flee their homes and are internally displaced due to regular cross-border shelling.

“A full-blown war between Israel and Hezbollah would be a catastrophic event for the region, including Israel and Lebanon,” Victor Tricaud, senior analyst at consulting firm Control Risks, told CNBC.

The most extreme war scenario? Tricaud describes a large-scale Israeli ground offensive and air strikes on Lebanon, heavy bombings by Hezbollah with regular direct hits on Israeli civilian infrastructure, and possibly even direct involvement by Iran, which would have serious consequences for the global economy.

A conflict of this magnitude would severely damage or destroy national infrastructure on both sides – such as water, electricity and communications systems – as well as homes and military targets.

But at the moment this is still “a relatively remote scenario,” said Tricaud. “Before the confrontation reaches such a level of intensity, many more escalation steps are likely to take place.”

Leaders on both sides say they do not want open war. Their exchanges in recent months, while sometimes deadly, are widely seen as carefully calculated to avoid a major escalation.

Lebanon, meanwhile, is in the midst of an economic and political crisis, and its infrastructure is completely unprepared for a new war. A large-scale Israeli invasion of the country would have catastrophic consequences, particularly in southern Lebanon – a major Hezbollah stronghold – and would seriously jeopardize the militant organization’s popularity and support there.

“Today, each side presumes to ‘teach’ the other that it can inflict greater pain within the accepted rules of engagement of limited combat,” says Nimrod Novik of the Israel Policy Forum, which advocates a two-state solution to the Israeli-Palestinian conflict.

“However, it is enough for a single misdirected missile to cause significant casualties and for the enemy to take appropriate retaliatory measures for the situation to get out of control.”

Hezbollah is considered one of the most heavily armed non-state groups in the world. Its military strength is estimated to be ten times that of Hamas. Most wars between Israel and Hezbollah have so far ended without a clear victory for either side.

The outcome of a 34-day war between the two adversaries in 2006, during which Israeli ground troops fought in Lebanon, was seen as a victory by Hezbollah, while Israel viewed it as a strategic failure. The militant group is now significantly stronger and equipped with more modern weapons than in 2006.

Tricaud said Hezbollah fighters were “increasingly battle-hardened through their participation in the war in Syria and could use asymmetric warfare tactics very effectively thanks to Hezbollah’s long-standing territorial control in southern Lebanon.”

He added that the consequences of a full-scale war for the Israeli population would be “far greater than in 2006.”

Retired Israel Defense Forces Colonel Miri Eisin, who currently heads the International Counterterrorism Institute in Israel, illustrated the threat posed by Hezbollah’s arsenal in the event of a full-scale war.

“We are talking about weapons that we have not seen in this area before,” she said, describing Hezbollah’s possible use of mortars, rockets, guided missiles, drone swarms, suicide drones and even ground troops to break down Israel’s defenses.

At the same time, Israel will “attack a large number of Hezbollah targets,” Eisin said. “And Hezbollah has surface-to-air missiles that it has rarely used so far, both from Iran and Russia.”

Despite Israel’s massive air defense systems, there will still be “capabilities that penetrate into the interior of Israel, which means there will be casualties in the heart of Israel,” she said.

In such a context, U.S. support for Israel will be critical; moreover, the stakes will be raised if other Iran-backed proxy groups intervene and attack American assets.

Recent reports have quoted anonymous US officials as saying the Biden administration will help Israel defend itself against Hezbollah retaliation. This could include maintaining the Iron Dome air defense system, providing intelligence – and possibly attacking Hezbollah itself in the event of major attacks on Israel. CNBC has reached out to the US Department of Defense for comment.

Novik of the Israel Policy Forum still believes that the diplomatic path to de-escalation and resolution has not yet been exhausted.

“In fact,” he said, “the tragic irony is that the greater the risk of escalation, the more willing the parties are to give space to diplomacy. It is a typical ‘uncomfortable’ situation.”