A cartoon circulated on Lebanon's social media recently showed a member of the Islamic State in Iraq and Syria (ISIS) attired in Lebanese garments. But with sunglasses emphasising the accompanying turban and white robes trimmed to miniskirt length, the man was wearing, instead of the usual desert sandals, high heels. The easy-going Lebanese are making fun of ISIS, which is now calling itself simply the Islamic State, having succeeded in uniting under its black Al-Qaeda-inspired banners large swathes of eastern Syria and western Iraq. But the joke belies the nervousness that this most westernised of all Arab countries, and least defensible, feels. Deep down, the Lebanese believe that their country is unlike any other in the region. Lebanon may have fallen victim to wars in the past, but the brand of ultra-conservative, pathological violence for which ISIS has been known doesn't sit well with a nation that embraces modernity with a passion. This much was stated recently by Lebanese Forces leader Samir Gaagaa, who said that the Sunnis of Lebanon could not tolerate ISIS. But the lightness of heart for which the Lebanese are famous is no defence against long tentacles of fanatical violence, as many Syrians and Iraqis may attest. Lebanon, in fact, is no stranger to the fault-lines through which the extremists seek traction in this region, these including class differences, sectarian tensions, disgruntled minorities, foreign intervention, ineffectual governments, refugee camps, and all the rest of them. ISIS is not at the gates of Lebanon. It has already entered. Although Lebanon may ostensibly be calmer than many countries in the region, extremists have found their ways through the cracks, and hundreds of them are already stationed in the Lebanese Beqaa Valley, biding their time. This disturbing fact was highlighted by a recent operation in a Beirut hotel, thought to be the handiwork of ISIS followers. Until recently, the Al-Nusrah Front used to be the top Sunni militant group of Syrian origin with a foothold in Lebanon. But this has changed after the recent victories of ISIS in Iraq, with some members of the Front deciding to leave their group to work for its former competitor instead. The place where ISIS and its allies congregate is the mountainous terrain around the predominantly Sunni village of Arsal close to the Syrian border, according to a Lebanese official who spoke on condition of anonymity. The official didn't rule out the possibility of battles between the Sunni militants of ISIS in the coming few weeks. Although at least one of the leaders of the Al-Nusrah Front, Abu Al-Hassan Al-Filistini, has joined ISIS, the Lebanese official said that the two hard-line organisations seemed to have overcome their differences, and were now often working in tandem. The official estimated the number of Sunni militants in the region, combining combatants of both ISIS and the Al-Nusrah Front, as some 3,000 to 4,000 men. He added that the Sunni local population was not particularly sympathetic to ISIS, no doubt having taken note of its harsh ideology and brutal tactics. Clashes have abated, however, between Hizbullah and the Syrian army on the one hand and the militants on the other. But this could be just the calm before the storm, the Lebanese official added. He pointed out that previous clashes had led to no changes in the positions held by the combatants on the ground. ISIS is a problem for everyone in Lebanon, from the Sunnis among whom the fighters hide, to the Shias who resent their ways, to the Lebanese army which is having trouble keeping up with their impressive combat readiness, to the secularists who don't want fanatics in their backyard. Hizbullah, which is not shy of taking on ISIS in battle, has had to restrain itself, for any excesses on its part could set Lebanon off down the slippery slope of sectarian war, the very thing the Sunni fanatics are praying for. The Lebanese army cannot possibly gather the firepower needed to suppress the hundreds of battle-hardened guerrilla fighters fresh from fighting the Syrian army next door. Of course, the Lebanese army could call on the Syrian army or on Hizbullah for help, but this would be a mistake in a country having the fragile temper that Lebanon has these days. The anti-Syrian, predominantly-Sunni 14 March Alliance, led by the Future Current, also could not ask its rival, the Shia Hizbullah, to help clean out the Beqaa Valley from ISIS. But allowing ISIS to strike roots in the Beqaa is a dangerous proposition for all established Lebanese parties – Sunni, Shia or otherwise. It should be recalled that ISIS obduracy is such that it has not been able to cooperate with like-minded fanatics in the field. So what use will it be to Lebanon's secularists, including those in the Future Current? The answer is as clear as it is disturbing.