Israel’s targeted killing of Hezbollah military leader Fuad Shukr in Beirut and Hamas political chief Ismail Haniyeh in Tehran are explosive events for the region. Coming within 12 hours of each other, they were also an earthquake within the “Axis of Resistance” — but not one likely to encourage de-escalation. Far from it. Iranian Supreme Leader Ayatollah Ali Khamanei has already declared Iran’s intention to exact revenge, as have the Islamic Revolutionary Guard Corps’ (IRGC) proxy leaders in Iraq and Syria, and the Houthis in Yemen.

When a dozen children were killed by a Hezbollah rocket in the Arab Druze town of Majdal Shams in the Israeli-occupied Golan Heights on Saturday, a significant Israeli response was always guaranteed. The decapitation of core leaders like Shukr and Haniyeh may create a brief moment of uncertainty within their groups’ ranks, and it underscores the extent to which Israel has penetrated the resistance axis’ highest levels. That Haniyeh was killed in an IRGC compound, in Tehran, when regional leaders were visiting for President Masoud Pezeshkian’s swearing-in, is a humiliation in the most palpable sense.

But while all actors have long claimed to want to avoid a full-blown war, this latest sequence of events brings us closer to that eventuality than at any point since Oct. 7. Israeli Prime Minister Benjamin Netanyahu himself declared today that “I have not and will not submit to voices calling for an end to the war” — far from encouraging rhetoric when the region sits on a knife-edge.

We’re now in a waiting game — to see how Hezbollah responds from Lebanon and what wider regional dimensions come into play. Nothing will happen until Haniyeh’s and Shukr’s funerals in Tehran and Beirut are complete and Hezbollah leader Hassan Nasrallah has spoken from Lebanon later today. Iran is likely now also backchanneling with regional states, in advance of its own response.

It seems almost guaranteed at this point that attacks on US troops in Iraq and Syria will resume. The five attacks against the Ain al-Asad and Conoco bases over the past two weeks could soon be dwarfed by events like what was seen prior to February, when over 200 attacks took place. With America entering into a decisive election season, the last thing the Democrats want is for US troops to be under fire and the Middle East aflame. Almost all of those 200-plus attacks that occurred between October 2023 and February 2024 were rudimentary in nature, intended primarily to symbolize hostility to the US rather than to draw it into direct combat. That could change this time around.

Meanwhile, the Houthis are well placed to continue their current scope of operations, to include targeting international shipping and long-range missile and drone strikes on Israel — whether Eilat or Tel Aviv. But it’s Hezbollah’s response that will likely guide where things go next.

While we’re unlikely to see any immediate surge into all-out war, any further acts of escalation would increase the risk of that scenario considerably. Almost all red lines have already been crossed. The fact that both Hezbollah and Iran now appear set to retaliate makes the risks of miscalculation far higher than if this were a one-front dynamic — even if they claim to want to avoid war. It is for this reason alone that the highest levels of the US government have been exerting all their diplomatic capital in recent hours into trying to convince the actors involved to take a breath, and a step back from the brink.

The 2006 Israel-Hezbollah war was devastating for the immediate region, but what could be around the corner would be far worse. For starters, Hezbollah is a completely different beast in 2024 than it was nearly two decades ago. In 2006, Hezbollah had no more than 15,000 rockets at its disposal, but today, it has 150,000 rockets and missiles, capable of reaching any target, many with precision-guidance technology installed. With such vast numbers, Hezbollah could swiftly overwhelm Israel’s world-leading layered air defense system, allowing heavy precision projectiles to target strategic Israeli infrastructure — both military and civilian.

To add to the complexity, Hezbollah now has a formidable array of one-way attack drones, many of which can “hug” the ground and evade radar sensors, approaching their target virtually invisibly. And that’s not to mention Hezbollah’s more than 25,000 full-time fighters, many of whom carry with them years of combat experience from Syria, where the group fought in close coordination with Russian elite Spetsnaz forces on critical frontlines. Altogether, Hezbollah poses a challenge to Israel that makes Hamas look like child’s play. Setting aside all the bluster, Israel knows this.

Until recently, continuing talks over a Gaza cease-fire offered the best chance for regional de-escalation. All of Iran’s regional axis — from Hamas in Gaza to Hezbollah in Lebanon, militias in Syria and Iraq to the Houthis in Yemen — would almost certainly halt their attacks if a full cease-fire came into effect in Gaza. But it is hard to see where those negotiations can go now. While Netanyahu’s actual willingness to cease fire has never really been clear, Hamas’ leader in Gaza, Yahya Sinwar, was a consistent obstacle too. With Haniyeh out of the way, that Sinwar hindrance now looks like a steel wall.

Thus, with the prospect of the core driver of regional hostilities (Gaza) ending now being near zero, we can only hope that calm heads will prevail. A series of carefully calculated retaliatory actions akin to what we saw in April could feasibly be managed, allowing for a gradual return to the pre-existing unstable status quo. But with such unprecedented developments now in play, that may be too optimistic a hope.

Charles Lister is a Senior Fellow and the Director of the Syria and Countering Terrorism & Extremism programs at the Middle East Institute.

Photo by HOSSEIN BERIS/Middle East Images/AFP via Getty Images