Could Hezbollah chief Nasrallah declare all-out war on Israel?

The people of Beirut have gone through a lot with a near-endless list of crises battering their city. Yet the past couple of weeks have delivered a new feeling of uneasiness to this seaside community of two and a half million.

"Either nothing is going to happen - or we are all going up there to be with God," said one fearful resident, gesturing skyward, as she talked about a widely anticipated speech by the Muslim cleric Hassan Nasrallah.

A passionate and fiery orator, Nasrallah is leader of the Shia political and military faction Hezbollah and is set to deliver his first public pronouncement since the 7 October Hamas attack, nearly a month after Israel began pulverising Gaza with bombs.

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The speech matters because the secretary general of Hezbollah is considered by many to be the single most powerful individual in Lebanon with as many as 100,000 fighters at his disposal.

It also matters because his address may help us understand whether Hezbollah is likely to open a second front on the northern Israeli border and turn what is a brutal conflict centred in and around Gaza into an unpredictable regional war.

Hassan Nasrallah was born in 1960 in east Beirut, where he was described as a devout and motivated student of Islam.

He joined Hezbollah in 1982 after the Israeli invasion and occupation of southern Lebanon.

Rising through the organisation, he replaced Hezbollah's leader, Abbas al Musawi, in 1992 after he - and members of his family - were assassinated in an Israeli airstrike.

In a number of interviews, Nasrallah has repeatedly refused to recognise the state of Israel, stating that he considers its existence to be unlawful and unjust.

He has offered contradictory comments on whether he would accept a two-state solution for Israelis and Palestinians but is seen as a key figure of the so-called "axis of resistance" - a coalition of anti-Israeli and anti-Western groups backed by Iran.

Most importantly perhaps, the 63-year-old has proven himself to be a capable military leader.

In a month-long war in 2006, Israel Defence Forces were surprised by the quality of Hezbollah's personnel and weapons as they used so-called "swarming" tactics to eliminate Israeli positions.

With financial support from Iran, Hezbollah has transitioned from a guerrilla outfit into something resembling a conventional army, with drones and rockets that can hit all parts of Israel, it claims.

However, the relative strength of Hezbollah's military brigades does not mean that Nasrallah is ready to plunge into an all-out war with Israel.

Crucially, he knows the Israelis will hit back - and hit hard.

Israeli Prime Minister Benjamin Netanyahu has warned Hezbollah it faces counter-strikes of "unimaginable" magnitude that will cause devastation in Lebanon.

The Americans are also key here.

White House National Security Council spokesman John Kirby said that they will be "paying close attention" to Nasrallah's speech.

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With two aircraft carrier groups now parked in the eastern Mediterranean, the US "will send a strong message to any actor who may want to widen the conflict", according to Kirby.

Equally important is the desperate situation at home as a caretaker government in Lebanon grapples with the consequences of a gruelling, four-year-long economic collapse.

The crisis, which has been widely blamed on corruption and incompetence amongst the governing elite, has impoverished the majority, with an estimated 80% living below the poverty line.

In a political space that Hezbollah shares with the representatives of parties from other political and religious communities, many Lebanese do not want to plunge into war.

A recent survey published in al Akhbar, a daily paper sympathetic to Hezbollah, found 68% of Lebanese opposed a "fully-fledged" campaign with Israel.

What Hezbollah is currently doing is fighting a localised conflict on the country's southern border with their fighters - and members of the Israel Defence Forces - trading fire at targets which, for the most part, straddle the frontier.

The fighting is sporadic yet constant, and it has also been deadly for Hezbollah.

At last count, 48 of its combatants have been killed as sophisticated Israeli drones target fighters manoeuvring in olive groves and brush.

Hezbollah released a handwritten letter from Nasrallah last week, saying the fallen fighters should be called "martyrs on the road to Jerusalem".

What seems clear is that Hezbollah's attacks have been calculated to avoid a big escalation, while keeping Israeli forces occupied in the north. Their leader's speech should provide us with a strong indication of whether they are inclined to keep it that way.