Politics in Indian states can often seem uniquely complex, but on closer inspection, patterns emerge that reveal both striking similarities and sharp differences. On the surface, Bihar and Tamil Nadu—two states separated by geography, language, and history—appear worlds apart. Yet, when it comes to political alliances and the role of national parties vis-à-vis state-based political forces, these two states share a peculiar resemblance.

Bihar and Tamil Nadu are notable for being among the very few major Indian states where the Bharatiya Janata Party (BJP) and the Congress Party—the two dominant national parties—are not the leading players. Instead, they serve as junior partners to regional parties that dominate the local political landscape.

In Bihar, the Congress is a junior partner of the Rashtriya Janata Dal (RJD), while the BJP aligns with the Janata Dal (United) or JD(U). Though the seat-sharing arrangements differ—with the RJD enjoying a roughly three-to-one advantage over Congress—the key takeaway is that the BJP must still acknowledge Nitish Kumar’s leadership in the state. Both the RJD and JD(U) emerged from the broader socialist stream of North Indian politics, tracing their roots back to splits in the Janata Dal during the 1990s.

Tamil Nadu, in contrast, sees the Congress acting as a junior partner to the Dravida Munnetra Kazhagam (DMK), while the BJP aligns with the All India Anna Dravida Munnetra Kazhagam (AIADMK). Both the DMK and AIADMK are offshoots of the Dravidian movement, with the AIADMK having split from the DMK in the 1970s following differences between M. Karunanidhi and M.G. Ramachandran.

A parallel between the two states emerges in the social base of these dominant parties. Both the RJD-JD(U) and DMK-AIADMK coalitions primarily draw support from backward castes, though not necessarily from the most socially marginalized groups, such as Scheduled Castes. In both Bihar and Tamil Nadu, the local vanguards of these parties have had histories of violence and oppression even as they profess commitment to social equality. However, the impact varies: in Bihar, the numerical dominance of upper castes has meant that socialists never fully displaced them from political influence, unlike in Tamil Nadu, where the Dravidian movement more comprehensively reshaped local power structures.

But here, the similarities largely end. Economically and socially, Bihar and Tamil Nadu could not be more different.Tamil Nadu ranks among India’s wealthiest and most developed states. Its prosperity is spread broadly rather than concentrated in a handful of cities, as seen in states like Maharashtra, Karnataka, or Haryana. This success is the result of multiple factors converging: the state fought the anti-caste struggle early, implemented affirmative action across sectors, and created a workforce capable of seizing the benefits of post-liberalisation economic growth. Political consensus in Tamil Nadu has largely prevented anti-capitalist policies from undermining development.

Bihar’s trajectory has been very different. The state’s social revolution largely focused on replacing upper-caste feudal lords with the so-called Subaltern Saheb, a term popularised by biographer Sankarshan Thakur in reference to Lalu Yadav. Unlike Tamil Nadu, Bihar’s revolution often disrupted the very infrastructure of growth. While Nitish Kumar’s administration has slowed further deterioration, it has struggled to lift the state economically. Consequently, material and human capital have migrated away from Bihar, often to states like Tamil Nadu, which has emerged as a magnet for talent from both within India and abroad.

The divergence extends into cultural and political superstructures. Tamil Nadu has historically resisted the hegemonic imposition of Hindi and centralizing forces, maintaining a distinct linguistic and cultural identity. This resistance—rooted in both a sense of superiority in socio-economic indicators and anxiety about demographic and fiscal pressures—has fortified DMK’s position against the BJP. Bihar, by contrast, has not had an analogous cultural-political bulwark, leaving it more vulnerable to the dominant narratives and polarizing strategies employed by the BJP in Hindi-speaking states.

This has profound implications for national politics. In states like Bihar, the BJP has consolidated power through a combination of social engineering and communal polarization, while Congress has struggled to maintain relevance. By focusing on lower OBCs and Dalits, Congress has attempted to counter BJP dominance, but its delayed efforts have left it disadvantaged. Congress’s efforts to adopt southern-state-inspired social justice strategies have been complicated by the perception of being anti-Hindi speaking, which the BJP exploits politically.

Some commentators have suggested that a pan-India social-justice coalition from Chennai to Patna could revive Congress. While there is some merit to this idea, it overlooks the deep structural differences between Tamil Nadu and Bihar that limit the transferability of political strategies. Bihar’s political economy, historical trajectory, and socio-cultural landscape differ fundamentally from those in Tamil Nadu, making any straightforward replication of Tamil Nadu-style success unlikely.

In summary, while Bihar and Tamil Nadu share the feature of national parties acting as junior partners to dominant regional forces, the economic, social, and cultural divergences between the states are far more consequential. Tamil Nadu demonstrates how inclusive social policies combined with broad-based economic growth can create a politically stable and prosperous state. Bihar, in contrast, shows the challenges of translating social revolution into material progress, particularly in the absence of enabling institutions and leadership.

Politics in India, therefore, is a study in contrasts and convergences. While alliances and party structures may mirror each other in unexpected ways, the underlying economic and cultural realities define the limits of similarity. Understanding these nuances is crucial for anyone attempting to decipher the complex mosaic of Indian state politics.