Israel will drive all the way to Baalbek, if I don't miss my guess, in order to occupy the missile and rocket-launching sites of Hezbollah. There are simply too many rockets--and now missiles with too long a range--for Israel to think they can use air power alone to destroy those missiles and rockets before they are launched:
Amid the chaos of Syria’s civil war, Hezbollah has been moving long-range missiles to Lebanon from bases where it had stored them inside Syria, including long-range Scud D missiles that can strike deep into Israel, according to an Israeli national security analyst. ...
Despite Israeli anti-rocket and anti-missile defenses, Israel doesn't have enough to protect all the civilians within range of all of Hezbollah's arsenal.
And let's add another reason for Israel to invade and really break apart Hezbollah--Iran lives or dies on Hezbollah's success:
Gen. Amir Ali Hajizadeh, the head of the [Revolutionary] Guard's aerospace division, said Israelis will see Hezbollah's new might should a war break out. Slain Hezbollah commander Hassan al-Laqis had played a key role in boosting the group's military strength, he added, without elaborating. The comments were posted on the Guard's website, sepahnews.com.
Well, "lives or dies" is an over-statement.
But Hezbollah works for Iran. Iran wants Hezbollah to be able to threaten Israel as an Iranian asset. Iran prefers to fight Israel to the last Arab, if they can--that's leading from behind.
So Israel can't afford to look at southern Lebanon as just a terrorism and bombardment problem. A weak Hezbollah weakens Iran.
So if Iran cheers on Hezbollah while Hezbollah rains high explosives down on Israeli civilians, Israel will have to launch a ground invasion to halt the attacks--and destroy as much of Hezbollah's infrastructure, leadership, and foot soldiers.
