An explosion in southern Lebanon last week destroyed what is believed to have been a Hezbollah weapons depot. This latest in a series of mysterious “accidents” in Hezbollah-controlled precincts proved, as one Israeli official wryly remarked, that those who “sleep with rockets and amass large stockpiles of weapons are in a very unsafe place.” With the Party of God’s overland supply route through Syria choked off by the 22-month-long uprising against Syrian president Bashar al-Assad, and Israel virtually in total control of the maritime route, Hezbollah’s stockpile is being systematically degraded.Yet the arsenal of Iran’s other regional proxy force, Hamas,...