Robert Fisk: Hezbollah has been lured into unknown territory in Syria as it wages costly battle for survival So Obama thunders on. Hezbollah must leave Syria. That will have them shaking in their boots in the Bekaa valley. For Hezbollah - 22 dead in one day a week ago, according to an acquaintance who should know - has no intention of withdrawing from a battle which threatens its existence in Lebanon. Casualties? Well huge, it seems - and we will come to that later. Here's a little story that may help to explain why the Shia Muslim Hezbollah, the most fearless and ruthless guerrilla army in the world, is in Syria. A major political mistake by its leader, Sayyed Hassan Nasrallah, no doubt. But not a major military one. For the Syrian war is in danger of flipping across into Lebanon; not in the northern Lebanese city of Tripoli, where its Sunni and Alawite (Shia) militias have long played out a symbolic struggle between each other. But in the dirt-poor town of Arsal, up in the hills beside the Syrian border scarcely 20 miles from the Hezbollah-held - and I mean "held" - Lebanese town of Hermel. Arsal - no tourist should waste their time here, though the people are kind and care for their town - is a Sunni and rather Salafist place. It supports the Sunni uprising against President Bashar al-Assad of Syria. If its Sunni rebel neighbours just over the border in Qusayr - most from the Islamist Jabhat al-Nusra (not the Free Syrian Army beloved of Obama and the US Senator John McCain) - capture Qusayr, they will be able to use the Lebanese town of Arsal as a place of rest and recreation and, indeed, rearming. Arsal is a mortar's range from the main highway between Hermel and the south of Lebanon, Hezbollah's two fiefdoms in Lebanon. Three Lebanese soldiers were killed in Arsal last week - quite probably because Syrian rebels don't want their movements in and out of Lebanon to be monitored. So Arsal and Hermel are the two most important towns in Lebanon right now. The Lebanese army has no checkpoints in Hermel - which is why armed Hezbollah men ride the range there - but it is determined to keep a tight hold on Arsal. Which is why the local anti-Assad men would prefer the Lebanese army left. And which is why the Lebanese President - a former general himself - went to visit the scene of the army killings himself last week. He did not go to Hermel where a young Shia woman was killed a few hours earlier by a missile almost certainly fired by Sunni rebels in Syria. These are not facts which make it into the headlines. And all praise to the fine journalism of the Christian French-language L'Orient Le Jour newspaper and especially its reporter Scarlett Haddad (she once admitted to me that her parents had named her after Scarlett O'Hara) for pointing out not only the battle-lines of northern Lebanon but the resilience of the Lebanese army which is now the only foundational block upon which Lebanon itself survives. For this is a country which has neither a functioning government nor a legal parliament - albeit that the assembly has just voted itself another 17 months of unelected power. But there are other events which have also eluded the headlines these past few days. Not the least is the interesting character shown next to Senator John McCain in a photograph during his recent visit to rebel-held northern Syria. For beside McCain can be seen a man identified here in Beirut as Mohammed Nour, a Sunni Muslim spokesperson for the Northern Storm Brigade, accused of kidnapping 11 Lebanese Shia pilgrims in Syria a year ago. What on earth was McCain doing with such a guy? If it was Nour, it was "regrettable," McCain's spokesman said. Quite so. Just as it was regrettable that no one in Washington appears to have condemned the killing of the young Shia woman in Hermel last week. Because she was a Shia? Or because the killers may have been Syrian rebels - who may or may not be the kind of rebels Obama (and Hague and other minions) would like to help. There are other things going on in Lebanon which the world should know about. Not least is the anger of Palestinians (the majority of them Sunnis) with Hezbollah. Last week, Palestinians at that most shameful of all refugee camps - at Ein el-Hilweh in Sidon - burnt Hezbollah food parcels beside a poster which said that "we don't want assistance soaked in the blood of the Syrian people." Hamas, the Palestinian controllers of Gaza, abandoned Damascus after the revolution began; now Hezbollah suspects Hamas has been teaching the Sunni rebels in Syria how to fight. Is this why Hezbollah is losing so many men? Shia fighters returning from Qusayr are telling frightening stories; that the Sunnis burn their bodies at night so that they should not be identified, that they have new sniper rifles. Interestingly, a Syrian military officer told me several months ago that when the rebels storm government bases, they retrieve the bodies of their dead with grappling hooks; again, so that there should be no identification. I asked an Afghan - always the trustiest source for such information - why Hezbollah was taking such huge casualties. Here is the reply I got: "In southern Lebanon, when they were fighting the Israelis, Hezbollah knew their own land and their own territory. They were fighting from home and the Israelis fell into the trap because they didn't know Lebanon. The occupied always know the territory better than the occupiers. But now Hezbollah are on unfamiliar territory. The Syrians know Qusayr. Hezbollah do not. A big "ouch." I guess Sayyed Nasrallah thinks about this.