Yes, sure. Even without the interference of Iran and others (such as Saudi Arabia), there would be tension in Lebanon. The country's current political regime is symbolized by the fragile balance between representatives of different communities. Lebanon is haunted by the specter of a long civil war, a truce held to a fragile bargain. A civil war may break out in the country again: Shiites x Sunnis x Christians, as happened for example in Iraq (Sunnis x Shiites). Meanwhile, Iran has long supported Shiite militias (he founded Hezbollah in the mid-eighties). Saudi Arabia represents Sunnis.