Political parties usually survive defeat. What they often struggle to survive is the sudden loss of power. That is the predicament facing the Trinamool Congress (TMC) party in West Bengal, a state of more than 100 million people in eastern India. Barely a month after being voted out of office , the party is facing a rebellion by most of its legislators, a potential split among its MPs and growing doubts about the authority of its founder, Mamata Banerjee. Banerjee is no ordinary regional leader.