Lebanon’s Prime Minister Saad Hariri was hosting a dinner earlier this month when a message came through on his phone. Guests say his demeanour “changed instantly”. He excused himself. Three hours later he was on a plane to Saudi Arabia. Next day he was on Saudi TV announcing his shock resignation. 

In a speech thought to have been written by Riyadh, the Saudi capital, Hariri blamed the Saudis’ arch enemy, Iran, and Iran’s proxy militia in Lebanon, Hezbollah. It left Lebanon stunned, including Hariri’s allies. Lebanon’s president suggested Hariri was essentially a Saudi hostage. Adding an air of the dramatic, Hariri said his life was in danger, evoking memories of his billionaire father Rafik, whose 2005 assassination – blamed on Hezbollah – provoked a minor revolution. Last week the Saudis ordered their citizens out of Lebanon. Within hours, Gulf allies did likewise.

What is going on, and why is it relevant to Israel?

Think of it like plate tectonics. After 38 years of building pressure, two of the great regional land masses – Sunni superpower Saudi Arabia and Shia superpower Iran – are colliding, triggering earthquakes. The next will be in Lebanon.

Why now? The new, all-powerful 32-year-old Saudi Crown Prince Mohammed bin Salman, whose ageing father sits on the throne, is desperate for a win. In the game of chess that is the muddled Middle East, the Saudis have lost several valuable pieces in Syria, where they bet on the rebels. We know because in October, leaked documents showed that Saudi Arabia’s intelligence minister ordered Syrian rebels to attack Damascus and “flatten the airport” in 2013, providing 120 tons of explosives and weapons to do so.

They didn’t flatten it, and didn’t win. Instead, Iran sided with President Bashar al-Assad, Hezbollah and the Russians triumphed. Worse, the young heir, who took control in 2015, is losing pieces in Yemen, too, where Saudi bombing to reinstate a puppet regime seems increasingly in vain – after two years attacking Iran-backed Houthi rebels, who refuse to be beaten, the Saudis are bogged down. In Iraq, too, the Saudis have lost their foothold. The government there is Shia (i.e. more friendly toward Iran) and Shi’ite militias are more useful than the Iraqi army.

Hezbollah supporters in Beruit

In short, what Jordan’s King Abdullah II has long warned of – the so-called Shia Crescent stretching from Iran to Lebanon – is now reality. The Saudis feel encircled, as does Israel, but all the noises are coming from Riyadh. When a ballistic missile was fired at the city’s airport from Yemen this month, Saudi Foreign Minister Abel Jabair called it “an act of war” by Iran. Likewise, Saudi’s Minister for Gulf Affairs Thamer al-Sabhan said last week that Lebanon’s government would “be dealt with as a government declaring war” because of Hezbollah’s “acts of aggression”.

In terms of sabre-rattling, it is deafening, but to what effect? Commentators say Iran has played a poor hand brilliantly, and is now able to flick the finger at Donald Trump continuing its missile development regardless of his tweets.

So why do the Saudis want to line up Lebanon as the next Sunni-Shia battleground? Everything suggests otherwise. Militarily, Hezbollah is the only game in town, far more powerful than the Lebanese army. Moreover, the Saudis would struggle to get there over unwelcoming Syrian airspace defended by advanced Russian missiles and an irritated President Assad. Even if they could, the Saudis are useless on the battlefield. Senior British diplomat Sir John Jenkins told a Jewish News-BICOM audience in Westminster this month the Saudis were “high capability, low competence,” whereas Iran could “control a battlefield, exercise command and control, plan logistics and sustain strategic intent over decades… That’s the bit that wins wars in the Middle East”.

Watch British diplomat Sir John Jenkins at the Jewish News-BICOM audience in Westminster:

That the Saudis are targeting Lebanon is not in doubt. Those listening closely have heard a subtle policy shift – whereas the Saudis always treated Hezbollah and Lebanon as different, now they’re treated as one. Likewise in Jerusalem, where Israeli Defence Minister Avigdor Lieberman said last month that the “Lebanese army has lost its independence and become an integral part of Hezbollah’s network”.

For two states who don’t officially talk, Israeli and Saudi statements now sound remarkably similar. The same language and sentiments can be heard in Hariri’s resignation speech. “Iran’s arm… has managed to impose a fait accompli on Lebanon through the power of its weapons,” he said. “They have built a state within a state.” They’re not just on the same page; they’re reading the same line.

For years, Israelis ‘in the know’ have pointed to a “convergence of interests” between Israel and the Gulf monarchies, hinting at behind-the-scenes coordination. Now may be when they act in concert. In Lebanon, Israel sees a host state for a hostile party, and the Saudis see the chance to bloody Iran’s nose with Hebrew fists.

How they combine is not yet clear but the Saudis have the money and Israel has the means, so one may help finance the other’s actions. Moreover, Israel’s Chief of Staff Lt. Gen. Gadi Eizenkot said just this week that Israel is “prepared to share information [with Saudi Arabia] if there is a need to do so”. The two may also plan a pincer movement, with the Saudis ordering the Syrian rebels they still control to attack Hezbollah from the east just as Israel attacks from the south. Hit from both sides at once, Hezbollah would struggle.

Does Israel have the appetite for another incursion into Lebanon? We’ve been there before, in 1978, 1982, 1993, 1995 and 2006, when 1.5 million people were displaced. Lebanon is not a place of happy memories for Israel, yet Hezbollah is not only still standing, it is battle-hardened from fighting in Syria, with a network of contacts and an arsenal of rockets.

Dug-in and dangerous, it can now be supplied via an open road from Tehran to Beirut, connecting a state that wants to wipe Israel from the map with a militia within range to do so.

Surely that’s a red line crossed for Israel, which now just needs a casus belli (cause of war), but Hezbollah leader Hassan Nasrallah thinks Israel won’t go in unless it can be assured of a “quick, decisive and inexpensive war,” which it can’t.

Where does all that leave us? Back with Saad Hariri, who flew back to a puzzled Lebanon this week after a puzzling stopover in France.

A pawn in an almighty game, the way he is manoeuvred over the coming weeks will be telling.