West Bengal polls and the possible role of defections
West Bengal’s polity since 2014 has been a story of growing polarisation. With the Communist Party of India (Marxist) led Left Front continuously losing ground against the All India Trinamool Congress (AITC) in election after election, the BJP started positioning itself as the principal opposition party in the state.
On December 19, home minister Amit Shah inducted a host of political leaders from the All India Trinamool Congress (AITC), the left parties and the Congress in West Bengal into the Bharatiya Janata Party (BJP). The most prominent among them is Suvendu Adhikari, who used to be a minister in the current West Bengal government and comes from a politically influential family in the East Midnapore district. Adhikari, who has been a Lok Sabha MP in the past was elected as the AITC MLA of Nandigram – a place which is associated with the anti-land acquisition struggle which ultimately brought the end of the 34-year-old Left Front government in 2011 -- in the 2016 elections. In states where it is a challenger, the BJP has traditionally leveraged defections to its advantage. Here are four charts which explain this strategy and the possible churn it will bring to the state’s politics.

To capture West Bengal, the BJP must win South Bengal
Among the largest states, and most populated in the country, West Bengal has a very diverse landscape. The state can broadly be divided into five parts. The hill and foothill region comprising of Darjeeling, Cooch Behar and Jalpaiguri districts is a separate sub-region. Then there are the northern districts of Maldah, and North and South Dinajpur. Murshidabad and Birbhum, which are situated in the central region of the state, make up the third. The three districts of WestMidnapore, Purulia and Bankura are an extension of the Chotanagpur plateau and referred to as Jangalmahal. However, the biggest sub-region in the state is what is popularly referred to as south Bengal. This includes the greater Kolkata region. Because South Bengal is also the most densely populated region in the state, it holds the key to power. An HT analysis using Trivedi Centre for Political Data (TCPD) shows that the eight south Bengal districts out of the total 19 in this region, account for 57% of assembly constituencies (ACs) in the entire state.
Even in 2019, the BJP could not crack South-Bengal
The BJP shocked the AITC by winning 18 out of the 42 Lok Sabha constituencies in the 2019 elections in West Bengal. An AC-wise breakup puts the BJP and AITC tally at 121 and 164 respectively. The halfway mark in the West Bengal assembly is 147. While the BJP’s gains in the state between 2014 and 2019 have been stellar, the AITC has been able to hold it back in south and central Bengal, traditionally, strongholds of the latter. 67 of the 121 AC segments the BJP won in the 2019 Lok Sabha came from the 94 ACs in hills, north Bengal and the Jangalmahal sub-regions. Of the 33 and 167 ACs in central and south Bengal, the BJP could win only 6 and 48. The AITC, on the other hand won 119 out of the 167 ACs in South Bengal even in the 2019 elections. Just holding on to south Bengal will increase the AITC’s chances of remaining in power.
Tailwinds to the BJP from usurping the left’s support-base are perhaps exhausted
West Bengal’s polity since 2014 has been a story of growing polarisation. With the Communist Party of India (Marxist) led Left Front continuously losing ground against the AITC in election after election, the BJP started positioning itself as the principal opposition party in the state. This was evident even before the 2019 Lok Sabha election results (https://bit.ly/3nCLHRs)
The BJP’s rise in West Bengal can be divided into two phases. In the 2014 elections, it significantly increased its vote share, primarily at the cost of the left. In 2019, it consolidated these gains and made inroads into the AITC’s vote bank as well. Even though the AITC had a lead in terms of overall vote-share, it was significantly behind the BJP in the hills, north-Bengal and the Jangalmahal sub-regions. If one were to assume that what is left of the left in West Bengal is its ideologically committed core voter base, which will not do business with the BJP, then the only way for the BJP to improve its performance, especially in south Bengal is to break away a section of the AITC’s Hindu voters. Leaders such as Suvendu Adhikari are the best way to achieve this task.
This strategy could trigger a huge communal polarisation in the state
West Bengal has the largest share of Muslim population in India after Jammu and Kashmir and Assam. According to the 2011 census, Muslims accounted for 27% in the state’s population. The Muslim population is not uniformly distributed in the state. While there are very few Muslims in the hills and Jangalmahal regions, they are present in large numbers in north, south and central Bengal. The two Muslim majority districts – Murshidabad (66% Muslim population) and Maldah (51%) – are in the central and north Bengal regions, respectively. Nearly half (49.9%) of the population in Uttar Dinajpur in North Bengal also Muslim. The maximum Muslim population in any other district of the state is only 37%.
This also means that the AITC’s current dominance in south and central Bengal is based on support from both Muslim and Hindus. As the BJP tries to wean away the Hindu faction of the AITC’s support base, even as Muslims gravitate towards the AITC in greater numbers – data from the CSDS-Lokniti post-poll survey shows that this process was already underway in West Bengal – the state could experience unprecedented communal polarisation, even violence. While political violence is a characteristic feature of the state, it has not taken a communal colour in the past.