Israel's attack on Hezbollah leader represents an alarming escalation in the conflict Hezbollah

Israel's apparent attempt to assassinate Hezbollah leader Sayyed Hassan Nasrallah in a massive attack on an underground headquarters in Beirut's southern suburbs marks the most alarming escalation in nearly a year of war between the Shiite militant organization and Israel.

Immediately after Israeli Prime Minister Benjamin Netanyahu's highly bellicose speech to the UN General Assembly – in which he appeared to directly threaten Iran and promise to further “humiliate” Hezbollah – the first reports of a massive attack emerged.

Within less than an hour, Israeli journalists with ties to the country's defense and security apparatus suggested that Nasrallah was the target and that he was in the headquarters area at the time of the attack.

That the attack was viewed as extremely significant was quickly confirmed by a series of statements from Israel – including a picture showing Netanyahu ordering the attack over the telephone from his New York hotel room.

After a series of Israeli escalations against Hezbollah this month – including targeted killings and the explosion of thousands of modified pagers and walkie-talkies supplied to the group – it is clearer than ever that the long-standing ground rules for the balance of deterrence apply between the two sides has blown away.

In the early months of the conflict with Hezbollah, which began on October 8 – a day after Hamas' attack from Gaza – it was largely assumed that Israel would not assassinate the militant group's most senior members. But in recent months these “red lines” have become increasingly blurred.

As the geographic reach of attacks on both sides has expanded deeper into Lebanon and Israel, Israeli operations have targeted increasingly senior Hezbollah commanders beyond those directly involved in attacks on the ground in southern Lebanon .

Indeed, diplomats and knowledgeable analysts in the region have indicated since the beginning of the year that one goal of the discreet back-and-forth between Israel and Hezbollah by U.S. special envoy Amos Hochstein and the group's intermediaries was to maintain understanding among the most senior figures would not be targeted by the militant group.

However, on the Israeli side, evidence has accumulated over the last two weeks that a significant escalation is being sought.

Claims of unsuccessful Hezbollah attacks against senior Israeli figures have been made by the country's security authorities. At the same time, it was also suggested that the Israeli escalation was aimed at countering the militant group's own plans to launch a major offensive.

All of this, it now seems clear, was the start of a long-planned and multi-pronged attempt to decapitate Hezbollah.

While it may take several days to fully understand the impact of Friday's strike, Netanyahu and his military chiefs have taken an enormous risk, not just on the situation in northern Israel, where tens of thousands have been displaced by the fighting, but also with the wider region and with the country's relationships with its international partners.

The move comes amid international efforts led by the United States and France to negotiate a three-week ceasefire with Hezbollah and represents a emphatic slap in the face to the Biden administration, which believed it had an assurance from Netanyahu that he would do so temporary ceasefire supported ceasefire.

Instead, it appears that Netanyahu and his military leadership were constantly secretly preparing the ground for an attack aimed at undermining the rhetorical flourishes of the Israeli prime minister's warnings to Hezbollah and Iran during his barely attended speech to the United Nations on Friday underline.

Above all, the attacks represent a direct challenge to Tehran, for which Nasrallah represents its most important strategic regional ally and whose tens of thousands of Iranian-supplied missiles aimed at Israel have long been seen as a key strategic antidote to preventing an Israeli attack on Iran itself.

Now all bets are off. Despite anonymous Israeli claims – later denied by the IDF – that they had destroyed up to 50% of Hezbollah's rocket arsenal of well over 100,000, this remains highly unlikely. And although Hezbollah's command and control capability has been significantly damaged, it is likely that it still has significant capabilities.

Other Iranian allies, including in Iraq, Syria and Yemen, have missiles and drones of their own that, while not as significant as Hezbollah's, could be brought into play – not necessarily just against Israel, but also against US targets.

Then the most important question arises: Can Iran accept an attack against Nasrallah or could it also become embroiled in a widening conflict? And whether the attack against the Hezbollah leader is intended by Israel as a prerequisite for an attack against Iran.

The Iranian embassy in Beirut justified this concern by condemning the Israeli airstrike, saying that the attacks “represent a serious escalation that changes the rules of the game” and that Israel will be “appropriately punished.”