This study delves into the profound security implications for Pakistan following the Taliban's reconquest of Afghanistan, analyzed through the lens of Realist Theory by Hans Morgenthau in International Relations. The research underscores the notion that states act predominantly in pursuit of power and survival within an anarchic international system, a concepts central to Realism. The Taliban's resurgence presents a complex geopolitical paradigm for Pakistan, historically intertwined with the Taliban, yet navigating a labyrinth of regional and global strategic interests. This paper examines the shifts in regional power dynamics and their impact on Pakistan's national security strategy. It also assesses how Pakistan's historical ties with the Taliban and its intricate relationships with neighboring countries and World power in South Asia, and the potential recalibration of Pakistan's foreign and security policies in the wake of these developments. Furthermore, the study explores the potential for regional instability, cross-border terrorism, and the shifting allegiances of major powers in the region. This research contributes to the understanding of the realist implications of geopolitical shifts in South Asia, offering a nuanced perspective on Pakistan's strategic maneuvers in a rapidly changing security landscape.