The concept of 'strategic depth' has historically shaped Pakistan's Afghanistan policy. Analyse its evolution and consequences for regional stability.

'Strategic depth' is the Pakistani military doctrine of treating Afghanistan as a rear buffer against India, allowing forces and assets to fall back westward and denying India a foothold on Pakistan's second frontier. Emerging after the Soviet withdrawal, it converted Afghanistan from a neighbour into a strategic asset — a choice whose costs Pakistan is now absorbing.

Evolution of the doctrine

• Genesis (1980s–90s): the Soviet withdrawal let Pakistan's military leadership recast Afghanistan as strategic depth vis-à-vis India, cultivating allied Islamist and militant proxies [1].
• Post-9/11 duality: the doctrine produced the "good Taliban/bad Taliban" distinction — coercing groups hostile to Pakistan while sheltering those seen as useful westward [1].
• Post-2021 reversal: the Taliban's return to Kabul was expected to deliver a friendly western neighbour, but the Afghan Taliban's support enabled the Tehrik-i-Taliban Pakistan (TTP) to move across the border, complicating Pakistani operations against it [2].
• Consolidation under Munir: Field Marshal Asim Munir has formalised military dominance through constitutional and legal reform [1] and hardened the line on Kabul, while diversifying westward — the Strategic Mutual Defence Agreement with Saudi Arabia (17 September 2025, Riyadh) makes an attack on one an attack on both [3].

Consequences for regional stability

• Blowback: the proxy instrument turned inward; TTP violence now makes the Pak-Afghan frontier Pakistan's most active theatre [2].
• Interstate friction: cross-border strikes and closures have made Pakistan-Afghanistan ties a recurring flashpoint, with the Durand Line unsettled [1].
• For India: militant infrastructure sustained under the doctrine remains a direct security concern, while Pakistan's new Gulf alignment adds a West Asian dimension — the MEA has said it will study the pact's implications for national security and regional stability [4].

Strategic depth thus evolved from an anti-India buffer into a source of Pakistan's own insecurity, showing that proxies cannot substitute for settled borders. Durable regional stability requires verifiable counter-terror action, normalised Pakistan-Afghanistan borders and revived regional connectivity — the direction India's neighbourhood policy already favours.