Will the conflict in Lebanon destroy the US-Iran ceasefire? Maybe, but it was already shaky

Just hours after the leaders of the United States, Israel and Iran reached a temporary ceasefire, it was clear that each party had its own version of what had been agreed to.

Hundreds of people in Lebanon have been killed in Israeli airstrikes in the past 24 hours, immediately threatening to undermine the fragile agreement.

Iran had insisted hostilities in Lebanon cease as part of the deal, but Israel argued Lebanon was not included. The result is an ongoing proxy conflict alongside the main war, which has been paused for two weeks.

Given the US seems uninterested in addressing the intractable issues at the heart of tensions in the Middle East, this result was somewhat inevitable. It seems the most likely outcome now is the US will back out while claiming victory, leaving the region’s prewar status quo largely intact.

The importance of Lebanon

Lebanon has not been an official part of the war in the region, and is not a party to the ceasefire. So why is it so central to the conflict?

Since the Iranian revolution of 1979, the Iranian regime has funded and armed anti-Israel movements in the region including Hezbollah in Lebanon, Hamas in Gaza and the Houthis in Yemen.

Throughout its history as a nation, Israel has at times occupied and held security “buffer zones” around its territory.

After the fall of leader Bashar al-Assad in 2024, Israeli forces conducted a military operation in southern Syria, occupying a demilitarised buffer zone in the southwest of the country. Israel has diplomatic agreements with Egypt and Jordan, leaving the focus on Iran and the proxies it supports. The proxies closest to Israel, and therefore of most concern from the government’s perspective, are Hamas in Gaza and Hezbollah in Lebanon. Since the October 7 attacks, the Israeli government has taken an offensive military approach to dealing with both groups. From the perspective of Israel, Hamas and Hezbollah are just as severe security threats as Iran. While both proxy groups have been severely degraded since 2023, they are still operating. Since the onset of the conflict with Iran, the Israeli government has taken the opportunity to extend a security buffer zone in southern Lebanon. Under President Benjamin Netanyahu, Israel is very unlikely to give up this ambition. For Trump’s part, it is unclear whether he could persuade Netanyahu to abandon it, or if he even wants to try. Will the ceasefire survive? Unless the US can bring Israel into line and convince Netanyahu to stop its action in Lebanon, the ceasefire will fall apart. Iran has insisted fighting in Lebanon must end as part of the agreement. This is the regime’s way of protecting and supporting its much-diminished proxies. As negotiations get underway for a more lasting deal, the issue of Lebanon will become a key sticking point. This is in part because resisting Israel and the US is not just politically expedient for Iran; it is at the core of the Iranian regime’s identity and existence. While deeper antagonism that drives tensions in the region remains unaddressed, there’s little prospect of lasting peace. Trump seems set on a US withdrawal from the war with Iran. The US leaves behind a security environment that upholds the existing tensions in the region. Iran and Israel will continue to engage in the tit-for-tat violence that led us here. A flawed exit strategy A key issue with Trump’s approach in the Middle East is he has no real interest in resolving the core issue of Israel’s place in the region. He’s shown little grasp of the deeper historical roots at play. What seems to be front of mind for Trump is the unpopularity of the war within the US. With Trump’s approval ratings at a record low and the conflict already dragging on longer than many expected, the president is looking for a way out. This might be why Iran’s ten-point plan, which was previously “not good enough”, is now a “workable basis on which to negotiate”.