Mass defections are often blamed on ambition. But history suggests that parties begin to fracture when they lose ideological purpose. The spate of mass defections and vertical splits witnessed over the past few years has become the subject of heated debates in television studios and extensive media coverage. The list is long - the undivided Shiv Sena, the NCP, the AAP, the TMC, the Shiv Sena (UBT), with speculation also rife about several others. The BJP’s aggressive strategy