Under a broiling hot midday sun on the south Lebanese-Israeli border this summer, an extraordinary and very angry meeting took place between two major generals: the 60-year-old Irish UN force commander in Lebanon and the 54-year-old deputy chief of staff of the Israeli army. Listening to them was the ambitious, pro-Israeli – but very inexperienced – US ambassador to the United Nations. The row between the two men appears to have been pre-planned by the Israelis to impress the highly impressionable Nikki Haley. It worked.

Haley had been helicoptered up to the border from Jerusalem on 8 June by Israeli General Aviv Kochavi for a tour regularly laid on for visiting – and gullible – US officials: a walk to the Lebanese frontier wire with many a fearful warning from the Israelis about Hezbollah “terrorists”, “secret” Hezbollah missile bunkers in UN-controlled territory and the failure of UN troops to “disarm” the “terrorists” in Lebanon. This is a familiar horror story, trotted out for American and other Western diplomats and politicians over more than 30 years.

All seemed bright sunshine and optimism when the UN force commander, General Mick Beary – one of Ireland’s most experienced UN peacekeepers with three tours of duty in Lebanon and postings to Iraq, Bosnia and Afghanistan behind him – explained to Haley that the situation on the Lebanese-Israeli border was stable, did not require further intervention and that the frontier was currently experiencing one of the most peaceful periods in its modern history. All true.

But not according to Kochavi – former Gaza divisional commander and Israeli ex-military intelligence director – who angrily told Beary that the UN was not doing its job and was frightened of entering Shiite villages in southern Lebanon for fear of confronting the pro-Iranian Hezbollah. Kochavi, say the Israelis, told Haley that the UN’s mandate should be changed to ensure its soldiers “disarmed” Hezbollah.

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Beary stood his ground. He had heard this kind of stuff before. The UN is supposed to operate alongside the sovereign Lebanese army to ensure Lebanese government control (and peace) in a narrow sector along the Lebanese border – not battle with Hezbollah on behalf of the Israelis as part of their proxy war against Iran.

A wiser person might have checked all this out. Haley might have reminded herself, for example, how often the Israelis have cried wolf before, how frequently their claims of hidden rockets had turned out to be untrue – not many years ago, they showed drone-taken photo images of “missiles” being taken from a bombed garage in southern Lebanon under the eyes of the UN. One of the UN soldiers, however, had taken a snapshot of the “missiles” from a few feet away – in which the “rockets” were clearly no more than the damaged roll-up corrugated front doors of the bombed garages. Haley might even have read a few books about Lebanon – in which every Israeli incursion has ended in utter disaster.

But no. Within 11 weeks, Haley was sounding off in the UN about Major General Beary’s “embarrassing lack of understanding about what is going on” in southern Lebanon, of how “blind” he was to the spread of illegal arms. Beary responded to this attack on his competence as an officer – which, needless to say, went down very badly in the general’s native Ireland – by repeating that there was no evidence of any increase in weaponry. “If there was a large cache of weapons,” he said, “we would know about it.”

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Now for the Department of Home Truths. Beary is right. But he also knows – as we all do who reside in Lebanon – that Hezbollah fighters live in the Shiite villages inside the UN zone. Of course they do. They are Shiites. These are their homes. And we also know that they have weapons. Hezbollah made this embarrassingly clear last April when they bussed a bunch of journalists down to the border – where reporters saw around a dozen Hezbollah men armed with rifles, machine guns and rocket launchers not far from the UN headquarters.

The UN were apparently unaware of the trip in advance and the Lebanese government was outraged afterwards, while Hezbollah preened themselves for showing to the reporters some new Israeli frontline listening devices on the other side of the border.

This was farce. But there are other, more disturbing elements to the story. There are indeed certain Shiite villages in southern Lebanon in which UN soldiers do not linger. And there is a small hilltop plateau – known locally as “the Iranian gardens” – inside which the UN do not stray. But it lies within their area of operations.

UNIFIL, the United Nations Interim Force in Southern Lebanon, has been around for almost 40 years, its 250 fatalities killed by an assortment of armed groups including Hezbollah, the Israelis and Palestinians. Its 15,000-strong force now monitors a ceasefire drawn up after the 2006 Israeli-Hezbollah war; their mandate also tasks them to ensure “the immediate cessation of all offensive military operations” by Israel. Israel’s constant overflights of Lebanon, going on for nigh on 40 years, are themselves in contravention of UN resolutions.

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None of this, however, justified Haley’s ignorance of southern Lebanon. Beary, she said, “seems to be the only person in south Lebanon who is blind to what Hezbollah is doing”. Alas, Haley seems to be the only diplomat in the UN who is blind to just how dangerous the situation in south Lebanon would be if it wasn’t for older fellers like Beary.

Kochavi, a shrewd lad if ever there was one in the Israeli higher command, is the one man who does not want another war along the border. Which is why, every time there is the remotest sniff of violence on the frontier, the Israelis are on to UN headquarters in Naqqoura to ask for help.

The Lebanese still fear that – having failed to engineer the overthrow of Bashar al-Assad in Syria and thus Iran’s Arab ally in the Middle East – the Israelis will kick off another war in Lebanon to get rid of Hezbollah, something they hopelessly failed to do in 2006 during a war which Hezbollah may not have won but which Israel certainly lost.

But Israel’s own threats against Lebanon long ago lost their sting. In my own files, I have repeated warnings from Israel that civilian villages would be attacked in the “next” war, that Lebanon will be smashed back 400 years with the utter destruction of its infrastructure. But the Israelis destroyed much of Lebanon’s civilian infrastructure in 1982 and 1996 and again in 2006. And Lebanon simply rebuilt itself with Saudi, Qatari and Kuwaiti money.

Israel has spent millions of dollars bombing Syrian, Iranian and Hezbollah forces inside Syria over the past five years. Throughout the entire Syrian war, it hasn’t fired a shot at Isis and has even allowed Islamist fighters to go to Haifa hospitals for medical treatment. But the folk Israel didn’t shoot at appear to be losing and the Shiite forces it did bomb appear to be winning. Which is why Israel is wondering just what Hezbollah now has in store for them.

Unfortunately – as Kochavi is well aware – Hezbollah keeps its missiles well north of the UN lines. After all, with a range stretching as far as the Negev desert in southern Israel, why should Hassan Nasrallah, the Hezbollah leader – who admittedly sometimes talks as if he’s the President of Lebanon – bunker his rockets inside the UN zone which is right on the border?

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In Washington, Donald Trump, who knows even less about Lebanon than Nikki Haley, talked to the Lebanese Prime Minister recently about the latter’s battle with Hezbollah – apparently unaware that Hezbollah has ministers in the Lebanese government and that Michel Aoun (the real President of Lebanon) supports the militia.

Under sane leadership, the US usually managed to broker ceasefires in past Lebanon wars. But the current problem is that the US President is mad. Nikki Haley is thus reduced to using a string of clichés in the UN worthy of Theresa May.

“Enough is enough,” she said of North Korea’s missile pirouetting. North Korea is “begging for war”. America would not go on “kicking the can down the road”. This kind of codswallop may have gone down well when she was governor of South Carolina, but it’s pretty sorry stuff to hear from a UN ambassador who tells a senior UN officer in Lebanon that he’s “blind” to his duties.