The CPI(M) is in the middle of its highest body meetings to decide on its alliance with the Congress for the West Bengal state elections. [Bengal polls 2016: JNU issue & 3 other reasons that may finalise Congress-CPM alliance in state]
But what made the CPI(M) in the state seriously consider the idea of allying with the Congress, which has been its traditional rival in the state polls, apart from the fact that both parties felt a common threat from the ruling Trinamool Congress (TMC)?
What the survey said
According to Bengali channel ABP Ananda, a survey carried out by AC Nielsen in January said that if the Lok Sabha election is held now, the Left's vote-share would go by one per cent from what it was during the 2014 general elections.
1% rise in Left's vote-share if LS polls are held now
It means the Left's vote share would go up to five per cent (it was just over four per cent in 2014) and that suggests that in terms of votes, the Left would poll 55 lakh votes (one per cent of around 55 crore votes that were polled in the 2014 elections).
As per survey, CPM-Cong's joint votes now can exceed that of the TMC now
Left's votes can go up to 1.83 crore if Bengal sees a surge by 30 lakh votes
Since Bengal (42) has more number of seats in the Lok Sabha than Kerala (20) and Tripura (2), the two other states where the Left is a significant player, hence a dominating portion of that increased number of votes would be from the eastern state it is believed (around 30 lakhs). This additional quantity would hence raise the Left's votes to 1.83 crore (from 1.53 crore polled in the 2014 LS elections).
Add Congress's 49 lakh or more votes to that, the figure will beat TMC's 2.12 crore votes (LS poll 2014)
The Congress, on the other hand, got 49 lakh votes in Bengal in the general elections. If the two parties make an alliance, then their combined votes would go to 2.32 crore, which is more than the TMC's 2.12 crore votes polled in the 2014 election.
Moreover, the survey has also predicted a two per cent decline in the NDA's vote-share (it was 17 per cent in Bengal in the last Lok Sabha election) and a corresponding two per cent rise in the UPA's vote-share. This convinced the CPI(M) leadership in Bengal that a tie-up with the Congress would do their prospects in the state dominated by Mamata Banerjee a world of good.