The Indian National Congress party has experienced a continuous political decline in West Bengal over the past five decades, shifting from a dominant force to a marginalized player in the state's political landscape. This sustained erosion of influence began in the late 1970s and has been further exacerbated by the rise of two distinct regional powers and, more recently, a national party's expansion.

The initial displacement of the Congress occurred with the ascent of the Communist Party of India (Marxist) (CPI(M))-led Left Front coalition. Under the leadership of Jyoti Basu, the Left Front secured a decisive victory in the 1977 state assembly elections, ending decades of Congress rule in West Bengal. This marked the beginning of a 34-year uninterrupted tenure for the Left Front, during which the Congress struggled to reclaim its former stronghold, often relegated to the primary opposition role. The shift saw a significant portion of Congress's traditional voter base migrating towards the Left Front, which effectively established a strong grassroots network and focused on land reforms and rural development.

Further diminishing the Congress's presence was the emergence of the Trinamool Congress (TMC), founded by Mamata Banerjee in 1998. Banerjee, a former Congress leader, capitalized on growing anti-incumbency sentiment against the Left Front and perceptions of Congress's ineffectiveness in challenging the dominant left-wing government. The TMC rapidly gained traction, attracting a substantial portion of the anti-Left vote bank that had historically supported Congress. This development splintered the opposition vote, making it increasingly difficult for Congress to mount a serious challenge to either the Left Front or the burgeoning TMC. By 2011, the TMC, often in alliance with Congress initially, successfully unseated the Left Front, establishing itself as the new ruling party in West Bengal.

In recent years, the Bharatiya Janata Party (BJP) has become another significant factor contributing to the Congress's continued marginalization. The BJP's electoral performance in West Bengal has seen a notable upswing, particularly since the 2014 and 2019 general elections. This growth has positioned the BJP as the principal opposition to the ruling TMC in several regions, further shrinking the political space for both the Congress and the Left Front. The BJP's strategy has involved consolidating a portion of the Hindu vote and focusing on issues distinct from those typically championed by the Congress, thus attracting a new segment of voters and challenging the established bipolar contest between the TMC and the Left-Congress alliance.

Consequently, the Congress party, which once held significant sway in West Bengal, now faces a complex political environment where it is often the fourth force, behind the TMC, BJP, and occasionally the Left Front. Its seat share in the state assembly and vote percentage have consistently declined over successive elections. As of recent electoral outcomes, the party struggles to secure a double-digit representation in the legislative assembly, indicating a profound and prolonged erosion of its electoral strength and organizational structure across the state. The path forward for Congress in West Bengal involves navigating a multi-party landscape where regional and national forces have largely overtaken its historical dominance.