A car bomb exploded this past Tuesday in the Bir al-Abed neighborhood of south Beirut.Though there were no fatalities, at least 53 people were wounded and the bomb left a crater two meters deep. Bir al-Abed is situated in the heart of the Dahiyeh section of the city – home to the headquarters of Hezbollah and the place of residence of many of its most senior cadres.A little-known Syrian rebel group, the Brigade 313 Special Forces, has claimed responsibility for the bombing on its Facebook page – citing Hezbollah’s involvement in Syria as its motive.The credibility of this claim of responsibility remains subject to doubt. But few in Lebanon doubt that the bombing formed part of the overflow of sectarian strife, taking place due to Hezbollah’s entry into the Syrian civil war on behalf of Bashar Assad’s regime.The Bir al-Abed car bombing is the latest in a chain of recent events which are gradually raising the sectarian temperature in Lebanon to a boiling point.While global and regional media attention focuses on events in Egypt, the Lebanese are witnessing an ominous deterioration toward possible renewed conflict.In contrast to previous episodes of civil strife in the country, this time around, Lebanon’s Christians are irrelevant. The emerging conflict, instead, is between Sunnis and Shi’ites.In late June, the Lebanese army fought a pitched battle in Abra near the southern port of Sidon, against supporters of the Sunni Salafi cleric Ahmed al-Assir. Assir has emerged in the last two years as the most prominent and outspoken Sunni critic of Hezbollah’s de facto domination of Lebanon.The battles began after followers of Assir ambushed an army checkpoint, triggering what looked like a preplanned assault on the cleric’s infrastructure in Abra. 18 soldiers and at least 29 of Assir’s gunmen were killed in the subsequent two-day battle, which ended with the storming of Assir’s headquarters on June 24. The firebrand Sunni has not been seen since; a warrant has been issued for his arrest.The fighting in the Sidon area, however, was not only between Assir’s followers and the Lebanese Armed Forces. Western reporters on the scene noted the arrival of Hezbollah fighters to the city, and their participation on the side of the army, against Assir.These Hezbollah elements included both regular Hezbollah fighters and members of the movement’s auxiliary Saraya al-Muqawama (Resistance Brigades) – a less well-trained body consisting of non-Shi’ite Lebanese who support Hezbollah.The role of Hezbollah in the Sidon events has been denied by movement spokesmen and downplayed by Lebanese officials, who prefer to deny the emergent sectarian strife in the country.It has been well-noted, however, in the Sunni Islamist circles from which Assir himself emerged.Large protests were held in the first days of July, in areas associated with the Salafi Islamist trend of which Assir is a part, and shots were fired in the air in the northern city of Tripoli. The Tariq Jdeideh neighborhood of Beirut, long associated with Sunni radicalism, also witnessed a large gathering.These areas also were the setting for raucous celebrations following the car bomb in Bir el-Abed. In Tripoli, Salafi activists gave out sweets to passersby in celebration of the bombing, in a practice reminiscent of Hezbollah and Hamas.It is not yet definitively clear whether this bombing was initiated by Lebanese Sunni Islamists or their counterparts in Syria, the Brigade 313 statement notwithstanding.The latter remains by far the most likely option. The Syrian rebels have made clear that they regard Hezbollah targets within Lebanon as fair game, because of the Lebanese Shi’ite movement’s intensive involvement in the Syrian conflict.Indeed, the Dahiyeh area has already been targeted. In May, two rockets were fired on the Shiyah district in the area. Syrian rebels have also struck on a number of occasions at the Shi’ite border town of Hermel, in retaliation for Hezbollah’s own cross-border activity.But the distinction between Syrian or Lebanese elements in this context is largely meaningless.If Syrian rebels did indeed carry out the Bir al-Abed attack, it means that elements among them now have both the will and the ability to physically plant a car laden with explosives in Hezbollah’s most security- rich and well-guarded environment.This could almost certainly only be achieved with the help of local allies.And if, by any chance, this bombing or other acts of violence do turn out to be the result of local initiatives, the rising Sunni Islamist anger and confidence in Lebanon is a direct result of the Sunni rebellion in Syria.Either way, what this bombing means is that in the last month, the Syrian civil war finally conclusively arrived in the heart of Lebanon.Responses to the attack were instructive. Former prime minister Sa’ad al-Hariri described it as an “attempt by the Israeli enemy to push Lebanon to strife by organizing terror attacks.”Such statements should be seen in the context of a widespread dread among non-Salafi and Hezbollah Lebanese at the prospect of renewed civil strife, of which the bombing may be a harbinger. Blaming the all purpose scapegoat Israel is a way of avoiding the evident reality of increasing sectarian tensions. The Lebanese are supposed to unite against the imaginary threat of Israeli car bombings in Beirut.But Hariri’s statement reflects the helplessness of the March 14 Alliance of which he is a part. The civilian politics of March 14 have long proved irrelevant against the guns of Hezbollah.Lebanon is in a state of political paralysis. There is much anger in the Lebanese Sunni population at the recent Abra events, also among supporters of March 14.The bombing in Bir el-Abed suggests a different approach to dealing with the deadlock.Given the political impasse, the obvious immovability of Hezbollah by any means other than force and the example of the Syrian rebellion, this approach is likely to become increasingly in evidence in the period ahead.