Step 1: Context of the 2014 Political Realignment:
From 1989 to 2014, Indian politics was characterized by a highly fragmented multi-party system, where no single national party could secure an absolute majority in the Lok Sabha. This necessitated "survivalist" coalition governments (such as the United Front, NDA-I, and UPA) where regional parties held significant leverage. However, the General Elections of 2014 marked a major structural shift.
Step 2: Factor 1 --- Transition to Single-Party Dominance ("Surplus-Majority" Coalition):
In 2014, the Bharatiya Janata Party (BJP) won 282 seats, crossing the simple majority threshold ($272$) on its own for the first time in 30 years. Although the BJP formed a coalition government with its pre-poll allies under the National Democratic Alliance (NDA), the coalition's nature changed from a "compelled, survival-based" alliance to a "surplus-majority" alliance. Because the leading party did not rely on its partners for constitutional survival, the internal power dynamic shifted heavily in favor of the central party.
Step 3: Factor 2 --- Decline in the Bargaining and Veto Power of Regional Allies:
In previous coalition eras, regional partners (e.g., DMK, TMC, or SP) frequently exercised veto power over major foreign and economic policy decisions (such as the Indo-US Civil Nuclear Deal or FDI in retail) by threatening to withdraw support. Post-2014, the single-party majority of the dominant national partner severely weakened the political leverage of these regional allies. The central leadership was able to centralize policy formulation and implement major national and ideological agendas with minimal institutional resistance from coalition partners.