An assembly by-election in a rural constituency would not have been of much moment were it not for the striking psephological swing, as evident in West Bengal’s Contai South constituency.

By any reckoning, the victory of the Trinamul candidate, Chandrima Bhattacharya, with a margin of 42,526 votes has strengthened the party’s fort, given the three percentage-point increase in the voteshare in comparison with the verdict in 2016.

The other critical facet is the decimation of the CPI-M in an East Midnapore segment that was once its bastion. Whether or not the party’s potential and/or traditional voters have switched their preference to the Bharatiya Janata Party ~ as Mamata Banerjee claims and Biman Bose affirms ~ can only be speculated upon at this juncture.

Suffice it to register that the Marxists will have to contend with a 24-percentage point decline in electoral support. As critical as the Trinamul victory is the fairly spectacular surge in support for the BJP ~ from a vote-share of 8.76 per cent in the Assembly election last year to 30.97 per cent now.

Even its critics will readily concede that the approximaterly 22 per cent surge in the span of a year is nothing short of remarkable. In the net, the saffronite party is the runner-up, and the Left will have to accept that it has finished the race in the also-ran category. In terms of optics, the BJP is the winner.

From zero representation in the assembly till a few years back, the party will now emerge as a strong contender for the position of a pivotal Opposition entity. If Contai South is held up as a case-study, the BJP has registered quite a surge from its position of a fringe player in Bengal’s electoral stakes.

Having said that, it is early days to speculate whether the BJP will be able to graduate to the position of the state’s principal Opposition party. But the process towards a possible “graduation degree” has predictably been viewed with consternation by the CPI-M.

There is little doubt that Banerjee’s social sector schemes ~ notably Sabuj Sathi, Kanyashree, and cycles for school students ~ have yielded dividend at the hustings. And the pitch has been reinforced if her whirlwind visits over the past few weeks to the districts of North and South Bengal are any indication.

Suffice it to register that the patron-client relationship has benefited Trinamul, as it once did the CPI-M through the panchayati raj and Operation Barga. For now, the ascendancy of the BJP, if on a limited scale, lends a new dimension to West Bengal politics.

Elections aside, its performance on Ram Navami was suitably robust. But it would be premature to imagine that Bengal politics is set to be redefined. Unpredictable is the swing of the pendulum.