The Left or more specifically the CPI(M) has declined in West Bengal, and every passing election simply cements that idea. Since the Mamata Banerjee government defeated them in 2011, they have failed to rebuild themselves, and this has influenced the condition of the CPI(M) nationally too.
Their last standing citadel which was the Siliguri Mahakuma Parishad has also fallen to the Trinamool recently.
In Bengal, the void left by the CPI(M) had been taken over by the BJP as the traditional Left vote bank shifted to BJP, with the sole purpose of defeating the Trinamool Congress. This has led experts to conclude that the Left is irreparably broken.

