Every summer, Lebanon welcomes Arabs from all over the Middle East to its seashore and mountain resorts as they seek relief from the overbearing heat in their desert home countries. But this year, the local economy got a boost from the arrival of two unlikely Arab visitors: Syria's President Bashar al-Assad and King Abdullah of Saudi Arabia, who arrived together on Friday. Until recently, the two heads of state were the leading figures in a regional rivalry played out in Lebanon — that between groups allied to Iran on the one hand and those backed by the U.S. on the other. The purpose of Assad and Abdullah's day trip was to meet with Lebanese leaders and discuss the implications of the potentially explosive upcoming report on the investigation into the 2005 assassination of former Lebanese Prime Minister Rafik Hariri. But while that report, due in September, is expected to dramatically raise the political temperature in Lebanon, the joint mission of the two regional heavyweights, whose allies have previously turned Beirut into a battlefield, was taken by many Lebanese as a sign that there will be no new Lebanese civil war. At least for now.Rumors have spread recently that the U.N. investigation into the car-bomb murder of former Saudi ally Hariri will result in indictments for members of Hizballah, the anti-Israel militia and Lebanon's largest Shi'ite Muslim political party, which is backed by Iran and Syria. Hizballah has dismissed the suggestion that its members could be charged as yet another plot against the organization. But bringing to book Hariri's killer, who like all of Lebanon's prime ministers are Sunni Muslim by law, has been a cause célèbre for Lebanon's Sunni Muslims.The potential for the finding to reignite hostilities in a country whose sectarian political system divides power between the country's major religious groups is clear. It was Hariri's death in 2005 that shattered the fragile understanding between Syria and Saudi Arabia, and between Lebanon's Sunnis and Shi'ites, that had ended the country's 15-year civil war in 1990. The Syrian army, which occupied Lebanon at the end of that war, provided political stability and security, while the Saudis provided the money for reconstruction. But when billionaire Hariri, the Saudi point man in Lebanon, was killed, U.N. investigators initially focused on senior members of the Assad regime, with whom Hariri had been quarreling in an effort to gain greater autonomy for Lebanon. The street protests that followed Hariri's death allowed Saudi Arabia and the U.S. and France to pressure Syria to grudgingly withdraw its forces from Lebanon. And the main regional stakeholders have been fighting for supremacy in Lebanon ever since.Most of the fighting in Lebanon since 2005 has involved Hizballah, which is now the most formidable military and political force in the country. Iran and Syria, which provide the Shi'ite organization with money and weapons, use the Lebanese militants as a proxy force against Israel, without risking a direct war with the Jewish state that they would probably lose. Since the Syrian departure left Hizballah exposed, the U.S. and Saudi Arabia have tried to contain the group to no avail. In 2006, the U.S. gave Israel the green light to invade Lebanon in the hope of destroying Hizballah after its fighters grabbed some Israeli soldiers in a cross-border raid, but the offensive failed to achieve its objective. In 2008, when the Saudi and American-backed Lebanese government tried take control of Hizballlah's military communications network and the airport in Beirut through which Hizballah receives weapons, Hizballah militants invaded Sunni Muslim West Beirut and wiped out street gangs loyal to the government and funded by the Saudis.Since then Saudi Arabia has retreated, conceding that sanctioning a Syrian role in Lebanon and leaving Hizballah intact would be better than watching its Sunni brethren in Beirut take another humiliating beating and seeing its Lebanese investments go up in smoke. After becoming Prime Minister last year, Saad Hariri, Rafik's son and Saudi Arabia's new main man in Lebanon, has followed Riyadh's lead and dropped his anti-Syrian rhetoric. He even traveled to Damascus in December to shake hands with Assad, the man whom many of Saad Hariri's followers believe is responsible for the death of his father. They would be angrier if so many of them weren't making so much money. The Syrian-Saudi détente has led to the longest stretch of stability and the biggest tourist boom the country has seen in years.But like an angry ghost, the Hariri report threatens to upset that uneasy but profitable status quo. By traveling to Beirut with Assad, Abdullah is signaling that there will be no Saudi support for its Sunni allies responding to any finding of Hizballah involvement by either taking matters to the street or upsetting the fragile political status quo. Absent powerful internal and international pressure, any indictments against Hizballah will be unenforceable. Sheikh Hassan Nasrallah, Hizballah's leader, has been in hiding since 2006, and if the whole Israeli army can't get him, a U.N. tribunal in the Hague isn't likely to fare any better.But just how long the Pax Saudi-Syriana will maintain stability Lebanon remains to be seen. Hizballah's existence as an armed state within the Lebanese state continues to be a volatile and unresolved issue. U.N. resolutions require that the movement be disarmed, and the U.S. accuses Syria of stepping up its weapons deliveries to Hizballah this year. A spark anywhere in the region — such as an Israeli attack on Iran's nuclear facilities — could yet start another fire in Lebanon.