Hezbollah operatives emerged onto the smoke-filled streets soon after an Israeli airstrike leveled a building in their urban stronghold, walkie-talkies tucked unobtrusively under their black T-shirts. The calm demeanor of the militants, who exuded low-key discipline despite their casual, civilian clothes and no display of weapons, contrasted Sunday with the images of chaos and destruction lacing neighborhoods just outside Beirut’s southern boundary: crumpled buildings, incinerated cars, shattered glass. Full Story