Why Bankipur bypoll loss will worry the BJP | Number Theory

The NDA in Bihar will have to work harder to preserve its ‘coalition of extremes’ than what worked for it.

One should not read too much in an isolated by-poll result. But political consultant turned politician Prashant Kishor’s (PK) victory in the Bankipur by-poll should worry the Bharatiya Janata Party (BJP) in Bihar. The reasons go beyond the optics of the fact that the assembly constituency (AC) was held by BJP’s current national president Nitin Nabin. Here are five data points which explain the argument.

Jan Suraaj Party supporters celebrate after party Prashant Kishor's victory on Monday. (ANI)

Why Bankipur bypoll loss will worry the BJP

• 
  Bankipur was a long-time BJP bastion

  Nitin Nabin became an MLA at the age of 26 when he contested a by-poll which was necessitated by the death of his father, Nabin Kishor Prasad Sinha, one of BJP’s most important leaders of his generation. At the time of his passing in 2006, Nabin Kishore Prasad Sinha had been a four-time MLA from Patna West AC, large parts of which became part of the Bankipur AC after the 2008 delimitation. In the 8 assembly and Lok Sabha elections in Bankipur since 2009 Lok Sabha, the BJP has never lost this seat even once and had polled a minimum of 59.1% vote share in this AC. This makes its latest vote share of 34.4% the lowest ever by a distance. Even in the 2025 assembly elections, the BJP’s vote share in Bankipur was the highest in all 101 ACs which it contested.
• 
  Prashant Kishor’s JSP performed extremely poorly in 2025 elections

  While PK received disproportionate limelight in the 2025 elections as well, the results were extremely disappointing for his party which polled just 3.4% vote share in state as a whole. PK himself did not even contest the elections, which many saw as a sign of him chickening out of the contest fearing a loss. Overall vote share aside, there was very little in terms of a silver lining for PK and his party even in AC-wise contests. The best performance by a Jan Suraaj Party (JSP) candidate in 2025 was in Marhaura assembly constituency with a vote share of 32.4%. JSP did not even finish second in any AC in the state. To lose its safest bastion in the state to a party which failed to make any mark in its debut elections, and not some strong established opposition party, will hurt the BJP even more.
• 
  At the core of the BJP’s worries will be the tension in its upper caste base

  The first author of this story has built multiple original databases which show that the BJP has done much better than its competitors, especially the Congress, in giving representation to Other Backward Classes (OBCs) in legislature and the executive. It is this social engineering which has allowed the BJP to surge ahead of its competitors in many states. However, Bihar is one state where the BJP has also enjoyed an overwhelming support from upper castes and maintained a quid-pro-quo of representation to preserve this deal. This is best seen in the BJP’s large advantage in share of upper caste MLAs, both historically and currently in Bihar, as was shown by the historical caste database of MLAs in Bihar. PK’s Bankipur victory over the BJP will also be seen as an upper caste challenger – PK comes from the Brahmin sub-caste – defeating the BJP in one of its biggest upper caste bastions. His victory will embolden the BJP’s upper caste supporters to argue that the party needs to do more to retain their support. Erring on the other side of the demand carries the risk of alienating the BJP’s newly developed and expanding OBC base in the state, which is exemplified in the choice of its current chief minister.
• Conclusion

  Neither of the data points described above should be inferred as the sign of a pre-ordained decline of the BJP or a meteoric rise of the JSP in the state. What they do tell us is that the NDA in Bihar, now under the leadership of BJP and Samrat Chaudhury, will have to work harder to preserve its ‘coalition of extremes’ than what worked for it under its original architect, Nitish Kumar, who is now, quasi-retired from politics.