New Delhi, May 9 -- The Bharatiya Janata Party's breakthrough in West Bengal has altered more than India's domestic political map. It has also changed the strategic calculus along India's eastern frontier, particularly in relation to Bangladesh, a country whose post-2024 political transition has increasingly tested New Delhi's patience.

For several years, the politics of river water sharing between India and Bangladesh had been constrained not merely by diplomacy, but also by the realities of federal politics within India itself. Any agreement on the Teesta River, in particular, required the concurrence of the government in West Bengal, whose leadership under Mamata Banerjee consistently resisted arrangements it believed would hurt North B...