Hezbollah, the Shia movement formed more than forty years ago in Lebanon, is one of the most thriving and heavily armed nonstate players in recent history. With tens of thousands of battle-hardened fighters and support from Iran, Hezbollah poses a severe threat. The group has also entered the Israel-Hamas war. The Houthis, Hezbollah’s partner and understudy in Yemen, have joined the fight and been attacked by the United States and the United Kingdom. There is a growing risk that the confrontation will expand further beyond Gaza and the Red Sea into a regional war, including Lebanon.

Over the years, Hezbollah grew from a terrorist network to a well-organized militia and a political movement that came to overwhelm Lebanon’s politics. Today, it is the single most muscular movement in Lebanon, a remarkable accomplishment for the long-suppressed and marginalised Shia community. Yet, while driving an impressive medical support and service distribution apparatus for its Shia constituents, Hezbollah has served as a destructive and irresponsible political spoiler at the national level, containing meaningful accountability and governance progress even as Lebanon remains embroiled in a catastrophic economic meltdown.

Israel and Lebanon Hezbollah have been keen to avoid a repetition of full-scale war. There have been regular firefights along the border, but they have not escalated into a war. In 2022, Lebanon and Israel bargained a maritime border agreement backed by Hezbollah with U.S. assistance.

In 2011, Hezbollah came to the protection of the Bashar al-Assad regime in Syria together with Iran and Russia. The aid enabled Assad to hold onto power through the Arab Spring and the Syrian civil war.

Moreover, Hezbollah is keen to show solidarity with Sunni Hamas in its war with Israel, which began with a devastating Hamas surprise attack on Israel on October 7, 2023. After that, incidents in the Israel-Lebanon border region have become more regular. 

Hezbollah’s arsenal of missiles and rockets has increased from 15,000 in 2006 to over 130,000 today. Beyond allowing Hezbollah and Iran to meddle in various countries of the Middle East, this arsenal is an instrument to deter adversaries from attacking Iran’s nuclear facilities. A military attack on Iran’s nuclear infrastructure will probably spark a massive attack on Israel by both Iran and Hezbollah. This has effectively deterred Israel even as Tehran has accelerated its nuclear program since the Trump administration drew from the Joint Comprehensive Plan of Action in 2018.

Today, Hamas and Hezbollah have been bound by the Yemeni Houthis, a Zaydi Shia group. The Houthis, Hezbollah, and Hamas all receive financial and material support from Iran. Along with pro-Iran Shia militias in Iraq and different actors in Syria, they form Iran’s Axis of Resistance to the United States. The Houthis had modelled themselves. Now, they routinely strike merchant ships in the Red Sea, significantly disrupting shipping. The Houthi raids on shipping in the Red Sea drove Washington to create a maritime alliance to protect international shipping. 

On January 11, 2024, the US and the United Kingdom ushered dozens of military strikes on Houthi targets in Yemen. Oman, Yemen’s neighbour, denounced the attacks, and Saudi Arabia has advised restraint because it rightly fears that military operations against the Houthis will spark a deterioration in Yemen’s cease-fire and renewed Houthi strikes on the kingdom after a decade of a bloody war.

For the Houthis, these strikes are only a continuance of U.S. support for the Saudi war that has endured a decade. They are dubious to be intimidated by air strikes.

Hezbollah is recreating a careful strategy in the Israel-Hamas war: highlighting its support for Hamas and inflicting severe costs on Israel while so far avoiding an all-out war with the latter. The carefully calibrated level of violence is naturally challenging to control and could break down at any moment.

The Biden administration has been demanding Israel not to attack Hezbollah and initiate a wider war. Its decision to send Lisa Johnson, a new U.S. ambassador with significant regional experience, to Beirut is a positive step, but the administration must redouble its measures to avoid escalation. The war in Gaza must cease. A sustainable and complete cease-fire in Gaza, which is currently being followed by U.S. partners, including Egypt and Qatar, is necessary to prevent an outbreak of regional conflict from Beirut to Sana’a. The situation is critical.