Analysts partly attributed the Marxists' downfall to unpopular policies aimed at kickstarting growth at the regional level.
"Their over-enthusiasm for industrialization led the Marxists to grab farmland and the party is now paying for its mistakes," said Sunita Roy, a political analyst.
Tainted MPs of 15th Lok Sabha
Fourteen people died in police firing last year during protests by Bengal farmers who insisted the Marxists forcibly acquired their land to set up an assembly plant for the world's cheapest car by India's Tata group.
"Heads will roll after an autopsy of the mistakes is over," Roy said. One of the prominent figures caught in the crosshairs is CPI(M) general secretary Prakash Karat.
"He should be out now," said Lok Sabha Speaker Somnath Chatterjee, who was expelled from the party last year.
Image: CPI(M) general secretary Prakash Karat addresses the politburo meeting at party office in New Delhi on Monday, May 18, 2009.