Wikileaks confirmed yet another suspected, but never confirmed, relationship between Lebanon and Israel. American diplomatic reports from 2008 detail discussions between the Lebanese defense minister and American officials. The Lebanese minister discussed how Israel could hit key Hezbollah targets, and cripple the Iranian backed Shia force. The minister also believed that Israel could take out Hezbollah without enraging the rest of Lebanon if the fighting was confined to Hezbollah held areas. It was also important that targets in Christian Lebanese areas not be bombed. While most Lebanese are hostile to Israel, they are also uneasy about the Iranian supported Hezbollah militia. Hezbollah gunmen basically control most of southern Lebanon, and the government feels unable to take on the Iranian backed force. Moreover, Lebanese don't want to fight another civil war, like the 1975-90 one that wrecked the country. This conflict led to the creation of Hezbollah, which appears to continue the civil war, and may put the Shia minority in control of the entire country (which is dominated by the 40 percent Christian and 20 percent Sunni minorities.)
Hezbollah is the Lebanese arm of the Iranian Shia revolution. The Islamic radicals who run a religious dictatorship in Iran, carried out a coup in the 1980s, taking control of the government during a desperate war with Iraq (which had invaded Iran in 1980). The religious zealots in Iran believe the world would be a better place if everyone were Moslem, of the Shia variety (which predominates in Iran and Lebanon, but not with 90 percent of Moslems, who prefer the Sunni, or other minor sects.) Iran also believes that Israel must be destroyed, and Iranian leaders have not been shy about repeating this again and again in public. Hezbollah leaders repeat this demand. This basic Hezbollah goal, the destruction of Israel, makes negotiations with Israel difficult.
The Shia Arabs are so feisty in Lebanon because, for the last thousand years, they have usually been persecuted by the majority Sunni. When Iran underwent a revolution in 1979, and was taken over by Shia clerics, it became the major supporter of Shia resistance movements everywhere in the Middle East. Iran became an ally of Syria, mainly because both of them were enemies of Iraq. Hezbollah received money (up to a hundred million of dollars a year) and weapons from Iran. This enabled the 1.5 million Lebanese Shia (about 40 percent of the population) to hold their own against the wealthier Christians and Sunnis during the civil war. Syria has nearly three million Shias as well, and is ruled by members of the Alawite religious minority (an eccentric Shia minority that is considered heretical even by some Shia). So getting cozy with Iran and the Lebanese Shia seemed like a good idea to Syria.
In addition to helping the Shia defend themselves, Hezbollah also addressed the relative poverty of the Lebanese Shia by using the Iranian money to set up schools and medical clinics. They also organized the production of opium and heroin in southern Lebanon, creating an operation that provides another hundred million dollars a year for Hezbollah operations, and jobs for Shia Arabs.
The Iranians got something in return, the ability to send organizers from Iran to recruit Lebanese Shia for a terrorist organizations. The Iranian Islamic radicals believe that Israel must be destroyed and the world converted to Islam. This puts them at odds with Sunni Islamic radicals, who also believe the world should be forcibly converted to Islam, but to the Sunni version of Islam. Shia only comprise about 11 percent of all Moslems, so the Sunnis don't take Iranian Shia radicals objectives seriously. In the meantime, Sunni and Shia radicals sometimes cooperate in their effort to kill infidels (non-Moslems.)