West Bengal SIR: Why Mamata Banerjee's biggest poll offensive could backfire for Trinamool

West Bengal Chief Minister Mamata Banerjee addresses a rally protesting the Special Intensive Revision in Kolkata. (PTI)

The political battle in West Bengal is once again circling back to the voter list, one of the state's oldest and most combustible issues. As the Election Commission of India (ECI) undertakes its Special Intensive Revision (SIR) of electoral rolls in the state, Chief Minister Mamata Banerjee has mounted a fierce, relentless attack on the process, terming it a "BJP conspiracy" and warning that the exercise is designed to erase the votes of minorities. But her aggressive campaign may carry political risks far greater than the immediate controversy she is seeking to ignite.

Why SIR matters in West Bengal

The voter list is not just a bureaucratic record in West Bengal but has been central to the rise and fall of governments in the state for decades. The TMC leadership alleges that the SIR is a tool to selectively remove Muslim voters by identifying undocumented Bangladeshi migrants, a demographic the party strongly depends on. Mamata has positioned herself as the protector of every resident, reiterating that “no one will be forced out of Bengal.”

The stakes are enormous. Bengal has more than 7 crore registered voters. The deletion of even 5-10 per cent of names (as in parts of Bihar), the political impact would be seismic, especially for the TMC which draws up to 90 per cent support in many Muslim-majority districts.

BJP sees an opening

In the 2021 Assembly election, the TMC secured 48 per cent votes and won 215 seats, limiting the BJP to 77 seats with 38 per cent vote share. However, by 2024 the BJP had already made sharp inroads again, winning 12 Lok Sabha seats and increasing its vote share to 38.7 per cent.

With the SIR now underway, the BJP is framing the exercise as a long-overdue clean-up of "illegal infiltrators", particularly in border districts such as Murshidabad, Malda and Uttar Dinajpur where undocumented Bangladeshi migration has long been a point of political contention. For the BJP, the SIR has become a strategic tool to reboot its "infiltration" narrative ahead of 2026.

The historical context

Voter roll controversies are hardly new in Bengal. After Bangladesh's Liberation War, lakhs of refugees crossed into the state. The Left Front government, which ruled from 1977 to 2011, incorporated many of them into its political base. In the 2002 SIR, nearly 28 lakh names were removed. At the time, Mamata Banerjee supported the clean-up, accusing the Left of inflating the rolls with illegal entries.

The BJP is now using Mamata's own history to turn her current opposition into a political weapon. The party argues that if she once backed deletion of illegal names, blocking the process now exposes her political vulnerability. The issue is sensitive across communities with not many takers -- irrespective of religion or caste -- for what they see as unchecked "outsider entry".

Why Mamata's stance could backfire

Mamata's bid to portray herself as the protector is running into a powerful social truth. Communities often resist demographic changes, even within their own faith. Local resentment against "outsiders", including undocumented migrants, is not limited to Hindus. In many Muslim-majority areas, long-settled local Muslims privately oppose the arrival of newer Bangladeshi Muslim groups who they fear may compete for welfare benefits, land rights or jobs.

This overwhelming sentiment complicates Mamata's narrative. While she frames the SIR as an "anti-Muslim" move by the BJP, local communal dynamics do not uniformly support her position.

The BJP, meanwhile, is tying SIR to the Citizenship Amendment Act (CAA), which has strong resonance among the Matua community, a crucial Hindu refugee electorate that has increasingly shifted towards the BJP.

The demographic risk

If 20–30 lakh names are removed during the SIR, a conservative estimate in the BJP's assessment, the TMC's most reliable vote base will take a heavy hit. Muslim voters are now estimated to be 31-33 percent of Bengal's population, with districts such as Murshidabad (70%)and Malda (55%) forming large chunks of the TMC's seat base.

A significant deletion of names in these regions could affect over 100 seats where the TMC's dominance hinges on consolidated minority votes.

On November 20, 2025, Mamata wrote to the Chief Election Commissioner demanding that the SIR be halted, citing the deaths of Booth Level Officers (BLOs) engaged in the process. BJP leader Suvendu Adhikari countered sharply, calling her protest an attempt to undermine the ECI. With the final electoral roll scheduled for release on February 7, 2026, the voter list has already become one of the defining battlegrounds ahead of the polls.

The damage potential

Mamata's messaging risks alienating many indigenous Bengali communities who believe the SIR is necessary for fairness. Her promise that "no one will be removed from Bengal" may inadvertently fuel fears that the TMC is protecting outsiders rather than locals, a narrative the BJP is aggressively attempting to amplify.

Across India, migration-related local resentment often cuts across religion. From Maharashtra's hostility towards UP-Bihar migrants to Rajasthan's discomfort with Hindu refugees from Pakistan, identity and resource concerns often overpower communal solidarity. And Bengal is no exception.