BEIRUT (Reuters) - Saad al-Hariri landed in Beirut on Tuesday, his media office said, returning home for the first time since he resigned as Lebanon s prime minister in a broadcast from Saudi Arabia and plunged his country into political crisis,  Hariri s sudden resignation on Nov. 4 thrust Lebanon to the forefront of a regional power struggle between the Sunni monarchy of Saudi Arabia and Shi ite Islamist Iran, whose powerful ally Hezbollah is part of the Lebanese government. 