The fragile centre can easily collapse the way it happened in Karnataka, though it may not have the benefit of alternate formation sans dissolution.
In this scenario the success by Left may encourage it to repeat the feat at a larger scale. Defeat of Left would create saner space left of Centre polity as well as chasten the Left. In Bengal, many present day leaders were in Bangla Congress, Congress(U), and other breakaway efforts, others are with TMC. Electoral arithmetic of alliance can tilt the scale decisively as it did in Bihar as well as take it out of lineage straits.
