Hizballah's firebrand leader made his name baiting Israel, but many of his countrymen regard him as a threat to Lebanon as well. Wielding the kind of political clout that would make Muqtada al-Sadr green with envy, Nasrallah, 50, engineered the downfall of the government in Beirut and installed a President he prefers. Nobody doubts who's really in charge.