In this universe, World War III began in July of 2006 when Syria and Iran launched a nuclear strike against Israel in retaliation for its attacks on Lebenon. The U.S. then declared war on them and a devastating nuclear exchange followed.
Hezbollah attacks several Israeli border towns with nuclear-armed rockets, which were secretly supplied to them by Syria. Israel declares war on Hezbollah, shortly after which Lebanon goes to war in support of them. The U.S. then declared war on Hezbollah and Lebanon.
A joint blockade by the two nations is enforced upon Lebanon. A series of nuclear strikes are launched, killing hundreds of thousands of people and crippling the nation's infrastructure.