West Bengal By-elections and what they mean for Opposition politics in the State

For the past several years, barring one or two exceptions, the party in power in West Bengal have won the bypolls in the State without much resistance from the Opposition parties. A victory in the Assembly elections would mean that the ruling party extends its electoral dominance to by-elections, civic and panchayat polls, and the party in power literally takes over all elected bodies and institutions.

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Despite these trends, the margin of victory of the Bharatiya Janata Party (BJP) in the recently concluded bypolls at Nandigram and Rejinagar is something that must ring alarm bells for the Opposition parties. The BJP won the Nandigram bypoll by a margin of 1.22 lakh votes, registering 76 % of the all the votes polled. At Rejinagar, the margin was 75,000, and the BJP candidate secured 63 % of the votes.

Mamata AITC candidate secured 1.87 % votes at Rejinagar

Before May 4, 2026, the Trinamool Congress, led by Mamata Banerjee, dominated the electoral politics, and the vote share of the party had increased to even 48%.

However, the defeat in the 2026 Assembly polls and the split of the party in the Lok Sabha and West Bengal Assembly have severely impacted its electoral prospects. The candidate of Mamata All India Trinamool Congress (AITC) nominated for the Nandigram Assembly seat withdrew at the last moment at Nandigram, prompting Mamata Banerjee to support the Congress candidate. At the Rejinagar Assembly seat, Mamata AITC candidate Rabiul Alam Chowdhury secured only 3847 votes, which is only 1.87 % of the total votes secured. This may be the lowest number of votes secured by the Trinamool Congress in the past two decades on any assembly seat.